Remove back link from 404 error page (#23222967 )

I've kept it for 400/403/500/csrffail for now, because they also have a "try again" link. Yes, both things have browser buttons, but they make it a *little* clearer to technical users what one could to next, and especially on csrffail, "step back" is always possible and possibly actually helpful.
Fix inconsistent singular/plural use in text (Z#23223585)
2026-06-17 02:21:05 +00:00 · 2026-02-17 09:31:24 +01:00 · 2026-02-17 09:31:08 +01:00 · 2026-02-16 15:13:24 +01:00 · 2026-02-16 13:40:00 +01:00 · 2026-02-16 10:59:44 +01:00
366 changed files with 220726 additions and 169217 deletions
@@ -26,10 +26,10 @@ jobs:
    runs-on: ubuntu-22.04
    steps:
      - uses: actions/checkout@v4
-      - name: Set up Python 3.11
+      - name: Set up Python 3.13
        uses: actions/setup-python@v5
        with:
-          python-version: 3.11
+          python-version: 3.13
      - uses: actions/cache@v4
        with:
          path: ~/.cache/pip
@@ -23,13 +23,13 @@ jobs:
    name: Tests
    strategy:
      matrix:
-        python-version: ["3.9", "3.10", "3.11"]
+        python-version: ["3.10", "3.11", "3.13"]
        database: [sqlite, postgres]
        exclude:
-          - database: sqlite
-            python-version: "3.9"
          - database: sqlite
            python-version: "3.10"
+          - database: sqlite
+            python-version: "3.11"
    services:
      postgres:
        image: postgres:15
@@ -6,10 +6,14 @@
 {%- else %}
  {%- set titlesuffix = "" %}
 {%- endif %}
+{%- set lang_attr = 'en' if language == None else (language | replace('_', '-')) %}
+
+{# Build sphinx_version_info tuple from sphinx_version string in pure Jinja #}
+{%- set (_ver_major, _ver_minor) = (sphinx_version.split('.') | list)[:2] | map('int') -%}
+{%- set sphinx_version_info = (_ver_major, _ver_minor, -1) -%}

 <!DOCTYPE html>
-<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
-<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
+<html class="writer-html5" lang="{{ lang_attr }}"{% if sphinx_version_info >= (7, 2) %} data-content_root="{{ content_root }}"{% endif %}>
 <head>
  <meta charset="utf-8">
  {{ metatags }}
@@ -18,59 +22,50 @@
  <title>{{ title|striptags|e }}{{ titlesuffix }}</title>
  {% endblock %}

-
-  {#- CSS #}
-  {%- for css in css_files %}
-    {%- if css|attr("rel") %}
-      <link rel="{{ css.rel }}" href="{{ pathto(css.filename, 1) }}" type="text/css"{% if css.title is not none %} title="{{ css.title }}"{% endif %} />
+    {#- CSS #}
+    {%- for css_file in css_files %}
+    {%- if css_file|attr("filename") %}
+    {{ css_tag(css_file) }}
    {%- else %}
-      <link rel="stylesheet" href="{{ pathto(css, 1) }}" type="text/css" />
+    <link rel="stylesheet" href="{{ pathto(css_file, 1)|escape }}" type="text/css" />
    {%- endif %}
-  {%- endfor %}
+    {%- endfor %}

-  {%- for cssfile in extra_css_files %}
-    <link rel="stylesheet" href="{{ pathto(cssfile, 1) }}" type="text/css" />
-  {%- endfor -%}
+    {#- FAVICON #}
+    {%- if favicon_url %}
+    <link rel="shortcut icon" href="{{ favicon_url }}"/>
+    {%- endif %}

-  {#- FAVICON
-      favicon_url is the only context var necessary since Sphinx 4.
-      In Sphinx<4, we use favicon but need to prepend path info.
-  #}
-  {%- set _favicon_url = favicon_url | default(pathto('_static/' + (favicon or ""), 1)) %}
-  {%- if favicon_url or favicon %}
-    <link rel="shortcut icon" href="{{ _favicon_url }}"/>
-  {%- endif %}
-
-  {#- CANONICAL URL (deprecated) #}
-  {%- if theme_canonical_url and not pageurl %}
+    {#- CANONICAL URL (deprecated) #}
+    {%- if theme_canonical_url and not pageurl %}
    <link rel="canonical" href="{{ theme_canonical_url }}{{ pagename }}.html"/>
-  {%- endif -%}
+    {%- endif -%}

-  {#- CANONICAL URL #}
-  {%- if pageurl %}
+    {#- CANONICAL URL #}
+    {%- if pageurl %}
    <link rel="canonical" href="{{ pageurl|e }}" />
-  {%- endif -%}
+    {%- endif -%}

-  {#- JAVASCRIPTS #}
-  {%- block scripts %}
-  <!--[if lt IE 9]>
-    <script src="{{ pathto('_static/js/html5shiv.min.js', 1) }}"></script>
-  <![endif]-->
-  {%- if not embedded %}
-  {# XXX Sphinx 1.8.0 made this an external js-file, quick fix until we refactor the template to inherert more blocks directly from sphinx #}
-      {%- for scriptfile in script_files %}
-        {{ js_tag(scriptfile) }}
-      {%- endfor %}
+    {#- JAVASCRIPTS #}
+    {%- block scripts %}
+    {%- if not embedded %}
+    {%- for scriptfile in script_files %}
+    {{ js_tag(scriptfile) }}
+    {%- endfor %}
    <script src="{{ pathto('_static/js/theme.js', 1) }}"></script>

+    {%- if READTHEDOCS or DEBUG %}
+    <script src="{{ pathto('_static/js/versions.js', 1) }}"></script>
+    {%- endif %}
+
    {#- OPENSEARCH #}
    {%- if use_opensearch %}
    <link rel="search" type="application/opensearchdescription+xml"
          title="{% trans docstitle=docstitle|e %}Search within {{ docstitle }}{% endtrans %}"
          href="{{ pathto('_static/opensearch.xml', 1) }}"/>
    {%- endif %}
-  {%- endif %}
-  {%- endblock %}
+    {%- endif %}
+    {%- endblock %}

  {%- block linktags %}
    {%- if hasdoc('about') %}
@@ -123,23 +118,23 @@
          {% endblock %}
        </div>

-        <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
-          {% block menu %}
-            {#
-              The singlehtml builder doesn't handle this toctree call when the
-              toctree is empty. Skip building this for now.
-            #}
-            {% if 'singlehtml' not in builder %}
-              {% set global_toc = toctree(maxdepth=theme_navigation_depth|int, collapse=theme_collapse_navigation, includehidden=True) %}
-            {% endif %}
-            {% if global_toc %}
-              {{ global_toc }}
-            {% else %}
+          {%- block navigation %}
+          {#- Translators: This is an ARIA section label for the main navigation menu -#}
+          <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="{{ _('Navigation menu') }}">
+              {%- block menu %}
+              {%- set toctree = toctree(maxdepth=theme_navigation_depth|int,
+              collapse=theme_collapse_navigation|tobool,
+              includehidden=theme_includehidden|tobool,
+              titles_only=theme_titles_only|tobool) %}
+              {%- if toctree %}
+              {{ toctree }}
+              {%- else %}
              <!-- Local TOC -->
              <div class="local-toc">{{ toc }}</div>
-            {% endif %}
-          {% endblock %}
-        </div>
+              {%- endif %}
+              {%- endblock %}
+          </div>
+          {%- endblock %}

          {% if theme_display_version %}
              {%- set nav_version = version %}
@@ -158,53 +153,42 @@
    <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">

      {# MOBILE NAV, TRIGGLES SIDE NAV ON TOGGLE #}
-      <nav class="wy-nav-top" role="navigation" aria-label="top navigation">
-        {% block mobile_nav %}
-          <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
-          <a href="{{ pathto('index') }}">{{ project }}</a>
-        {% endblock %}
-      </nav>
+        <nav class="wy-nav-top" aria-label="{{ _('Mobile navigation menu') }}" {% if theme_style_nav_header_background %} style="background: {{theme_style_nav_header_background}}" {% endif %}>
+            {%- block mobile_nav %}
+            <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
+            <a href="{{ pathto(master_doc) }}">{{ project }}</a>
+            {%- endblock %}
+        </nav>

-
-      {# PAGE CONTENT #}
-      <div class="wy-nav-content">
-        <div class="rst-content">
-          {% include "breadcrumbs.html" %}
-          <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
-           <div itemprop="articleBody" class="section">
-            {% block body %}{% endblock %}
-           </div>
-           <div class="articleComments">
-            {% block comments %}{% endblock %}
-           </div>
-          </div>
-          {% include "footer.html" %}
+        <div class="wy-nav-content">
+            {%- block content %}
+            {%- if theme_style_external_links|tobool %}
+            <div class="rst-content style-external-links">
+            {%- else %}
+            <div class="rst-content">
+            {%- endif %}
+            {% include "breadcrumbs.html" %}
+            <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
+                {%- block document %}
+                <div itemprop="articleBody">
+                    {% block body %}{% endblock %}
+                </div>
+                {%- if self.comments()|trim %}
+                <div class="articleComments">
+                    {%- block comments %}{% endblock %}
+                </div>
+                {%- endif%}
+            </div>
+            {%- endblock %}
+            {% include "footer.html" %}
+        </div>
+        {%- endblock %}
        </div>
-      </div>
-
    </section>

  </div>
  {% include "versions.html" %}

-  {% if not embedded %}
-
-    <script type="text/javascript">
-        var DOCUMENTATION_OPTIONS = {
-            URL_ROOT:'{{ url_root }}',
-            VERSION:'{{ release|e }}',
-            COLLAPSE_INDEX:false,
-            FILE_SUFFIX:'{{ '' if no_search_suffix else file_suffix }}',
-            HAS_SOURCE:  {{ has_source|lower }},
-            SOURCELINK_SUFFIX: '{{ sourcelink_suffix }}'
-        };
-    </script>
-    {%- for scriptfile in script_files %}
-      <script type="text/javascript" src="{{ pathto(scriptfile, 1) }}"></script>
-    {%- endfor %}
-
-  {% endif %}
-
  {# RTD hosts this file, so just load on non RTD builds #}
  {% if not READTHEDOCS %}
    <script type="text/javascript" src="{{ pathto('_static/js/theme.js', 1) }}"></script>
@@ -214,7 +198,7 @@
  {% if theme_sticky_navigation %}
  <script type="text/javascript">
      jQuery(function () {
-          SphinxRtdTheme.StickyNav.enable();
+          SphinxRtdTheme.Navigation.enable({{ 'true' if theme_sticky_navigation|tobool else 'false' }});
      });
  </script>
  {% endif %}
@@ -1,136 +1,86 @@
-{#
-    basic/layout.html
-    ~~~~~~~~~~~~~~~~~
-
-    Master layout template for Sphinx themes.
-
-    :copyright: Copyright 2007-2013 by the Sphinx team, see AUTHORS.
-    :license: BSD, see LICENSE for details.
-#}
-{%- block doctype -%}
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
-  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-{%- endblock %}
-{%- set reldelim1 = reldelim1 is not defined and ' &raquo;' or reldelim1 %}
-{%- set reldelim2 = reldelim2 is not defined and ' |' or reldelim2 %}
-{%- set render_sidebar = (not embedded) and (not theme_nosidebar|tobool) and
-                         (sidebars != []) %}
+{# TEMPLATE VAR SETTINGS #}
 {%- set url_root = pathto('', 1) %}
-{# XXX necessary? #}
 {%- if url_root == '#' %}{% set url_root = '' %}{% endif %}
 {%- if not embedded and docstitle %}
  {%- set titlesuffix = " &mdash; "|safe + docstitle|e %}
 {%- else %}
  {%- set titlesuffix = "" %}
 {%- endif %}
+{%- set lang_attr = 'en' if language == None else (language | replace('_', '-')) %}

-{%- macro relbar() %}
-    <div class="related">
-      <h3>{{ _('Navigation') }}</h3>
-      <ul>
-        {%- for rellink in rellinks %}
-        <li class="right" {% if loop.first %}style="margin-right: 10px"{% endif %}>
-          <a href="{{ pathto(rellink[0]) }}" title="{{ rellink[1]|striptags|e }}"
-             {{ accesskey(rellink[2]) }}>{{ rellink[3] }}</a>
-          {%- if not loop.first %}{{ reldelim2 }}{% endif %}</li>
-        {%- endfor %}
-        {%- block rootrellink %}
-        <li><a href="{{ pathto(master_doc) }}">{{ shorttitle|e }}</a>{{ reldelim1 }}</li>
-        {%- endblock %}
-        {%- for parent in parents %}
-          <li><a href="{{ parent.link|e }}" {% if loop.last %}{{ accesskey("U") }}{% endif %}>{{ parent.title }}</a>{{ reldelim1 }}</li>
-        {%- endfor %}
-        {%- block relbaritems %} {% endblock %}
-      </ul>
-    </div>
-{%- endmacro %}
+{# Build sphinx_version_info tuple from sphinx_version string in pure Jinja #}
+{%- set (_ver_major, _ver_minor) = (sphinx_version.split('.') | list)[:2] | map('int') -%}
+{%- set sphinx_version_info = (_ver_major, _ver_minor, -1) -%}

-{%- macro sidebar() %}
-      {%- if render_sidebar %}
-      <div class="sphinxsidebar">
-        <div class="sphinxsidebarwrapper">
-          {%- block sidebarlogo %}
-          {%- if logo %}
-            <p class="logo"><a href="{{ pathto(master_doc) }}">
-              <img class="logo" src="{{ pathto('_static/' + logo, 1) }}" alt="Logo"/>
-            </a></p>
-          {%- endif %}
-          {%- endblock %}
-          {%- if sidebars != None %}
-            {#- new style sidebar: explicitly include/exclude templates #}
-            {%- for sidebartemplate in sidebars %}
-            {%- include sidebartemplate %}
-            {%- endfor %}
-          {%- else %}
-            {#- old style sidebars: using blocks -- should be deprecated #}
-            {%- block sidebartoc %}
-            {%- include "localtoc.html" %}
-            {%- endblock %}
-            {%- block sidebarrel %}
-            {%- include "relations.html" %}
-            {%- endblock %}
-            {%- block sidebarsourcelink %}
-            {%- include "sourcelink.html" %}
-            {%- endblock %}
-            {%- if customsidebar %}
-            {%- include customsidebar %}
-            {%- endif %}
-            {%- block sidebarsearch %}
-            {%- include "searchbox.html" %}
-            {%- endblock %}
-          {%- endif %}
-        </div>
-      </div>
-      {%- endif %}
-{%- endmacro %}
+<!DOCTYPE html>
+<html class="writer-html5" lang="{{ lang_attr }}"{% if sphinx_version_info >= (7, 2) %} data-content_root="{{ content_root }}"{% endif %}>
+<head>
+  <meta charset="utf-8" />
+  {%- if READTHEDOCS and not embedded %}
+  <meta name="readthedocs-addons-api-version" content="1">
+  {%- endif %}
+  {{- metatags }}
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  {%- block htmltitle %}
+  <title>{{ title|striptags|e }}{{ titlesuffix }}</title>
+  {%- endblock -%}

-{%- macro script() %}
-    <script type="text/javascript">
-      var DOCUMENTATION_OPTIONS = {
-        URL_ROOT:    '{{ url_root }}',
-        VERSION:     '{{ release|e }}',
-        COLLAPSE_INDEX: false,
-        FILE_SUFFIX: '{{ '' if no_search_suffix else file_suffix }}',
-        HAS_SOURCE:  {{ has_source|lower }},
-        SOURCELINK_SUFFIX: '{{ sourcelink_suffix }}'
-      };
-    </script>
+  {#- CSS #}
+  {%- for css_file in css_files %}
+    {%- if css_file|attr("filename") %}
+      {{ css_tag(css_file) }}
+    {%- else %}
+      <link rel="stylesheet" href="{{ pathto(css_file, 1)|escape }}" type="text/css" />
+    {%- endif %}
+  {%- endfor %}
+
+  {#
+      "extra_css_files" is an undocumented Read the Docs theme specific option.
+      There is no need to check for ``|attr("filename")`` here because it's always a string.
+      Note that this option should be removed in favor of regular ``html_css_files``:
+      https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-html_css_files
+  #}
+  {%- for css_file in extra_css_files %}
+    <link rel="stylesheet" href="{{ pathto(css_file, 1)|escape }}" type="text/css" />
+  {%- endfor -%}
+
+  {#- FAVICON #}
+  {%- if favicon_url %}
+    <link rel="shortcut icon" href="{{ favicon_url }}"/>
+  {%- endif %}
+
+  {#- CANONICAL URL (deprecated) #}
+  {%- if theme_canonical_url and not pageurl %}
+    <link rel="canonical" href="{{ theme_canonical_url }}{{ pagename }}.html"/>
+  {%- endif -%}
+
+  {#- CANONICAL URL #}
+  {%- if pageurl %}
+    <link rel="canonical" href="{{ pageurl|e }}" />
+  {%- endif -%}
+
+  {#- JAVASCRIPTS #}
+  {%- block scripts %}
+  {%- if not embedded %}
    {%- for scriptfile in script_files %}
-    <script type="text/javascript" src="{{ pathto(scriptfile, 1) }}"></script>
+      {{ js_tag(scriptfile) }}
    {%- endfor %}
-{%- endmacro %}
+    <script src="{{ pathto('_static/js/theme.js', 1) }}"></script>

-{%- macro css() %}
-    <link rel="stylesheet" href="{{ pathto('_static/' + style, 1) }}" type="text/css" />
-    <link rel="stylesheet" href="{{ pathto('_static/pygments.css', 1) }}" type="text/css" />
-    {%- for cssfile in css_files %}
-    <link rel="stylesheet" href="{{ pathto(cssfile, 1) }}" type="text/css" />
-    {%- endfor %}
-{%- endmacro %}
+    {%- if READTHEDOCS or DEBUG %}
+    <script src="{{ pathto('_static/js/versions.js', 1) }}"></script>
+    {%- endif %}

-<html xmlns="http://www.w3.org/1999/xhtml">
-  <head>
-    <meta http-equiv="Content-Type" content="text/html; charset={{ encoding }}" />
-    {{ metatags }}
-    {%- block htmltitle %}
-    <title>{{ title|striptags|e }}{{ titlesuffix }}</title>
-    {%- endblock %}
-    {{ css() }}
-    {%- if not embedded %}
-    {{ script() }}
+    {#- OPENSEARCH #}
    {%- if use_opensearch %}
    <link rel="search" type="application/opensearchdescription+xml"
          title="{% trans docstitle=docstitle|e %}Search within {{ docstitle }}{% endtrans %}"
          href="{{ pathto('_static/opensearch.xml', 1) }}"/>
    {%- endif %}
-    {%- if favicon %}
-    <link rel="shortcut icon" href="{{ pathto('_static/' + favicon, 1) }}"/>
-    {%- endif %}
-    {%- if theme_canonical_url %}
-    <link rel="canonical" href="{{ theme_canonical_url }}{{ pagename }}.html"/>
-    {%- endif %}
-    {%- endif %}
-{%- block linktags %}
+  {%- endif %}
+  {%- endblock %}
+
+  {%- block linktags %}
    {%- if hasdoc('about') %}
    <link rel="author" title="{{ _('About these documents') }}" href="{{ pathto('about') }}" />
    {%- endif %}
@@ -143,67 +93,135 @@
    {%- if hasdoc('copyright') %}
    <link rel="copyright" title="{{ _('Copyright') }}" href="{{ pathto('copyright') }}" />
    {%- endif %}
-    <link rel="top" title="{{ docstitle|e }}" href="{{ pathto('index') }}" />
-    {%- if parents %}
-    <link rel="up" title="{{ parents[-1].title|striptags|e }}" href="{{ parents[-1].link|e }}" />
-    {%- endif %}
    {%- if next %}
    <link rel="next" title="{{ next.title|striptags|e }}" href="{{ next.link|e }}" />
    {%- endif %}
    {%- if prev %}
    <link rel="prev" title="{{ prev.title|striptags|e }}" href="{{ prev.link|e }}" />
    {%- endif %}
-{%- endblock %}
-{%- block extrahead %} {% endblock %}
-  </head>
-  <body>
-{%- block header %}{% endblock %}
-
-{%- block relbar1 %}{{ relbar() }}{% endblock %}
-
-{%- block content %}
-  {%- block sidebar1 %} {# possible location for sidebar #} {% endblock %}
-
-    <div class="document">
-  {%- block document %}
-      <div class="documentwrapper">
-      {%- if render_sidebar %}
-        <div class="bodywrapper">
-      {%- endif %}
-          <div class="body">
-            {% block body %} {% endblock %}
-          </div>
-      {%- if render_sidebar %}
-        </div>
-      {%- endif %}
-      </div>
  {%- endblock %}
+  {%- block extrahead %} {% endblock %}
+</head>

-  {%- block sidebar2 %}{{ sidebar() }}{% endblock %}
-      <div class="clearer"></div>
-    </div>
-{%- endblock %}
+<body class="wy-body-for-nav">

-{%- block relbar2 %}{{ relbar() }}{% endblock %}
+  {%- block extrabody %} {% endblock %}
+  <div class="wy-grid-for-nav">
+    {#- SIDE NAV, TOGGLES ON MOBILE #}
+    <nav data-toggle="wy-nav-shift" class="wy-nav-side">
+      <div class="wy-side-scroll">
+        <div class="wy-side-nav-search" {% if theme_style_nav_header_background %} style="background: {{theme_style_nav_header_background}}" {% endif %}>
+          {%- block sidebartitle %}
+
+          {# the logo helper function was removed in Sphinx 6 and deprecated since Sphinx 4 #}
+          {# the master_doc variable was renamed to root_doc in Sphinx 4 (master_doc still exists in later Sphinx versions) #}
+          {%- set _logo_url = logo_url|default(pathto('_static/' + (logo or ""), 1)) %}
+          {%- set _root_doc = root_doc|default(master_doc) %}
+          <a href="{{ pathto(_root_doc) }}"{% if not theme_logo_only %} class="icon icon-home"{% endif %}>
+            {% if not theme_logo_only %}{{ project }}{% endif %}
+            {%- if logo or logo_url %}
+              <img src="{{ _logo_url }}" class="logo" alt="{{ _('Logo') }}"/>
+            {%- endif %}
+          </a>
+
+          {%- if READTHEDOCS or DEBUG %}
+            {%- if theme_version_selector or theme_language_selector %}
+              <div class="switch-menus">
+                <div class="version-switch"></div>
+                <div class="language-switch"></div>
+              </div>
+            {%- endif %}
+          {%- endif %}
+
+          {%- include "searchbox.html" %}
+
+          {%- endblock %}
+        </div>
+
+        {%- block navigation %}
+        {#- Translators: This is an ARIA section label for the main navigation menu -#}
+        <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="{{ _('Navigation menu') }}">
+          {%- block menu %}
+            {%- set toctree = toctree(maxdepth=theme_navigation_depth|int,
+                                      collapse=theme_collapse_navigation|tobool,
+                                      includehidden=theme_includehidden|tobool,
+                                      titles_only=theme_titles_only|tobool) %}
+            {%- if toctree %}
+              {{ toctree }}
+            {%- else %}
+              <!-- Local TOC -->
+              <div class="local-toc">{{ toc }}</div>
+            {%- endif %}
+          {%- endblock %}
+        </div>
+        {%- endblock %}
+      </div>
+    </nav>
+
+    <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
+
+      {#- MOBILE NAV, TRIGGLES SIDE NAV ON TOGGLE #}
+      {#- Translators: This is an ARIA section label for the navigation menu that is visible when viewing the page on mobile devices -#}
+      <nav class="wy-nav-top" aria-label="{{ _('Mobile navigation menu') }}" {% if theme_style_nav_header_background %} style="background: {{theme_style_nav_header_background}}" {% endif %}>
+        {%- block mobile_nav %}
+          <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
+          <a href="{{ pathto(master_doc) }}">{{ project }}</a>
+        {%- endblock %}
+      </nav>
+
+      <div class="wy-nav-content">
+      {%- block content %}
+        {%- if theme_style_external_links|tobool %}
+        <div class="rst-content style-external-links">
+        {%- else %}
+        <div class="rst-content">
+        {%- endif %}
+          {% include "breadcrumbs.html" %}
+          <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
+          {%- block document %}
+           <div itemprop="articleBody">
+             {% block body %}{% endblock %}
+           </div>
+           {%- if self.comments()|trim %}
+             <div class="articleComments">
+               {%- block comments %}{% endblock %}
+             </div>
+           {%- endif%}
+          </div>
+          {%- endblock %}
+          {% include "footer.html" %}
+        </div>
+      {%- endblock %}
+      </div>
+    </section>
+  </div>
+  {% include "versions.html" -%}
+
+  <script>
+      jQuery(function () {
+          SphinxRtdTheme.Navigation.enable({{ 'true' if theme_sticky_navigation|tobool else 'false' }});
+      });
+  </script>
+
+  {#- Do not conflict with RTD insertion of analytics script #}
+  {%- if not READTHEDOCS %}
+    {%- if theme_analytics_id %}
+    <!-- Theme Analytics -->
+    <script async src="https://www.googletagmanager.com/gtag/js?id={{ theme_analytics_id }}"></script>
+    <script>
+      window.dataLayer = window.dataLayer || [];
+      function gtag(){dataLayer.push(arguments);}
+      gtag('js', new Date());
+
+      gtag('config', '{{ theme_analytics_id }}', {
+          'anonymize_ip': {{ 'true' if theme_analytics_anonymize_ip|tobool else 'false' }},
+      });
+    </script>

-{%- block footer %}
-    <div class="footer">
-    {%- if show_copyright %}
-      {%- if hasdoc('copyright') %}
-        {% trans path=pathto('copyright'), copyright=copyright|e %}&copy; <a href="{{ path }}">Copyright</a> {{ copyright }}.{% endtrans %}
-      {%- else %}
-        {% trans copyright=copyright|e %}&copy; Copyright {{ copyright }}.{% endtrans %}
-      {%- endif %}
    {%- endif %}
-    {%- if last_updated %}
-      {% trans last_updated=last_updated|e %}Last updated on {{ last_updated }}.{% endtrans %}
-    {%- endif %}
-    {%- if show_sphinx %}
-      {% trans sphinx_version=sphinx_version|e %}Created using <a href="http://sphinx-doc.org/">Sphinx</a> {{ sphinx_version }}.{% endtrans %}
-    {%- endif %}
-    </div>
-    <p>asdf asdf asdf asdf 22</p>
-{%- endblock %}
-  </body>
-</html>
+  {%- endif %}

+  {%- block footer %} {% endblock %}
+
+</body>
+</html>
@@ -39,7 +39,7 @@ as well as the type of underlying hardware. Example:
       "rsa_pubkey": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqh…nswIDAQAB\n-----END PUBLIC KEY-----\n"
   }

-The ``rsa_pubkey`` is optional any only required for certain fatures such as working with reusable
+The ``rsa_pubkey`` is optional any only required for certain features such as working with reusable
 media and NFC cryptography.

 Every initialization token can only be used once. On success, you will receive a response containing
@@ -208,20 +208,6 @@ Additionally, when creating a device through the user interface or API, a user c
 the device. These include an allow list of specific API calls that may be made by the device. pretix ships with security
 policies for official pretix apps like pretixSCAN and pretixPOS.

-Removing a device
-----------------
-
-If you want implement a way to to deprovision a device in your software, you can call the ``revoke`` endpoint to
-invalidate your API key. There is no way to reverse this operation.
-
-.. sourcecode:: http
-
-   POST /api/v1/device/revoke HTTP/1.1
-   Host: pretix.eu
-   Authorization: Device 1kcsh572fonm3hawalrncam4l1gktr2rzx25a22l8g9hx108o9oi0rztpcvwnfnd
-
-This can also be done by the user through the web interface.
-
 Event selection
 ---------------

@@ -117,7 +117,7 @@ List-level conditional fetching
 If modification checks are not possible with this granularity, you can instead check for the full list.
 In this case, the list of objects may contain a regular HTTP header ``Last-Modified`` with the date of the
 last modification to any item of that resource. You can then pass this date back in your next request in the
-``If-Modified-Since`` header. If the any object has changed in the meantime, you will receive back a full list
+``If-Modified-Since`` header. If any object has changed in the meantime, you will receive back a full list
 (if something it missing, this means the object has been deleted). If nothing happened, we'll send back a
 ``304 Not Modified`` return code.

@@ -46,28 +46,28 @@ Endpoints
      Vary: Accept
      Content-Type: application/json

-   {
-      "count": 3,
-      "next": null,
-      "previous": null,
-      "results": [
-         {
-            "id": 2,
-            "start": "2025-08-14T22:00:00Z",
-            "end": "2025-08-15T00:00:00Z"
-         },
-         {
-            "id": 3,
-            "start": "2025-08-12T22:00:00Z",
-            "end": "2025-08-13T22:00:00Z"
-         },
-         {
-            "id": 14,
-            "start": "2025-08-15T22:00:00Z",
-            "end": "2025-08-17T22:00:00Z"
-         }
-      ]
-   }
+      {
+         "count": 3,
+         "next": null,
+         "previous": null,
+         "results": [
+            {
+               "id": 2,
+               "start": "2025-08-14T22:00:00Z",
+               "end": "2025-08-15T00:00:00Z"
+            },
+            {
+               "id": 3,
+               "start": "2025-08-12T22:00:00Z",
+               "end": "2025-08-13T22:00:00Z"
+            },
+            {
+               "id": 14,
+               "start": "2025-08-15T22:00:00Z",
+               "end": "2025-08-17T22:00:00Z"
+            }
+        ]
+      }

   :param organizer: The ``slug`` field of the organizer to fetch
   :param event: The ``slug`` field of the event to fetch
@@ -60,6 +60,9 @@ The following values for ``action_types`` are valid with pretix core:
    * ``pretix.event.added``
    * ``pretix.event.changed``
    * ``pretix.event.deleted``
+    * ``pretix.giftcards.created``
+    * ``pretix.giftcards.modified``
+    * ``pretix.giftcards.transaction.*``
    * ``pretix.voucher.added``
    * ``pretix.voucher.changed``
    * ``pretix.voucher.deleted``
@@ -211,7 +211,7 @@ The line-based computation has a few significant advantages:

 The main disadvantage is that the tax looks "wrong" when computed from the sum. Taking the sum of net prices (420.15)
 and multiplying it with the tax rate (19%) yields a tax amount of 79.83 (instead of 79.85) and a gross sum of 499.98
-(instead of 499.98). This becomes a problem when juristictions, data formats, or external systems expect this calculation
+(instead of 500.00). This becomes a problem when juristictions, data formats, or external systems expect this calculation
 to work on the level of the entire order. A prominent example is the EN 16931 standard for e-invoicing that
 does not allow the computation as created by pretix.

@@ -1,9 +1,8 @@
-sphinx==7.4.*
-jinja2==3.1.*
-sphinx-rtd-theme
-sphinxcontrib-httpdomain
-sphinxcontrib-images
-sphinxcontrib-jquery
-sphinxcontrib-spelling==8.*
-sphinxemoji
+sphinx==9.1.*
+sphinx-rtd-theme~=3.1.0
+sphinxcontrib-httpdomain~=2.0.0
+sphinxcontrib-images~=1.0.1
+sphinxcontrib-jquery~=4.1
+sphinxcontrib-spelling~=8.0.2
+sphinxemoji~=0.3.2
 pyenchant==3.3.*
@@ -1,10 +1,9 @@
 -e ../
-sphinx==7.4.*
-jinja2==3.1.*
-sphinx-rtd-theme
-sphinxcontrib-httpdomain
-sphinxcontrib-images
-sphinxcontrib-jquery
-sphinxcontrib-spelling==8.*
-sphinxemoji
+sphinx==9.1.*
+sphinx-rtd-theme~=3.1.0
+sphinxcontrib-httpdomain~=2.0.0
+sphinxcontrib-images~=1.0.1
+sphinxcontrib-jquery~=4.1
+sphinxcontrib-spelling~=8.0.2
+sphinxemoji~=0.3.2
 pyenchant==3.3.*
@@ -3,7 +3,7 @@ name = "pretix"
 dynamic = ["version"]
 description = "Reinventing presales, one ticket at a time"
 readme = "README.rst"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 license = {file = "LICENSE"}
 keywords = ["tickets", "web", "shop", "ecommerce"]
 authors = [
@@ -29,18 +29,19 @@ dependencies = [
  "arabic-reshaper==3.0.0",  # Support for Arabic in reportlab
  "babel",
  "BeautifulSoup4==4.14.*",
-  "bleach==6.2.*",
-  "celery==5.5.*",
+  "bleach==6.3.*",
+  "celery==5.6.*",
  "chardet==5.2.*",
  "cryptography>=44.0.0",
-  "css-inline==0.18.*",
+  "css-inline==0.20.*",
  "defusedcsv>=1.1.0",
+  "dnspython==2.*",
  "Django[argon2]==4.2.*,>=4.2.26",
-  "django-bootstrap3==25.2",
-  "django-compressor==4.5.1",
-  "django-countries==7.6.*",
+  "django-bootstrap3==26.1",
+  "django-compressor==4.6.0",
+  "django-countries==8.2.*",
  "django-filter==25.1",
-  "django-formset-js-improved==0.5.0.4",
+  "django-formset-js-improved==0.5.0.5",
  "django-formtools==2.5.1",
  "django-hierarkey==2.0.*,>=2.0.1",
  "django-hijack==3.7.*",
@@ -49,22 +50,22 @@ dependencies = [
  "django-localflavor==5.0",
  "django-markup",
  "django-oauth-toolkit==2.3.*",
-  "django-otp==1.6.*",
-  "django-phonenumber-field==7.3.*",
+  "django-otp==1.7.*",
+  "django-phonenumber-field==8.4.*",
  "django-redis==6.0.*",
  "django-scopes==2.0.*",
  "django-statici18n==2.6.*",
  "djangorestframework==3.16.*",
-  "dnspython==2.7.*",
+  "dnspython==2.8.*",
  "drf_ujson2==1.7.*",
  "geoip2==5.*",
  "importlib_metadata==8.*",  # Polyfill, we can probably drop this once we require Python 3.10+
  "isoweek",
  "jsonschema",
-  "kombu==5.5.*",
+  "kombu==5.6.*",
  "libsass==0.23.*",
  "lxml",
-  "markdown==3.9",  # 3.3.5 requires importlib-metadata>=4.4, but django-bootstrap3 requires importlib-metadata<3.
+  "markdown==3.10.2",  # 3.3.5 requires importlib-metadata>=4.4, but django-bootstrap3 requires importlib-metadata<3.
  # We can upgrade markdown again once django-bootstrap3 upgrades or once we drop Python 3.6 and 3.7
  "mt-940==4.30.*",
  "oauthlib==3.3.*",
@@ -72,33 +73,32 @@ dependencies = [
  "packaging",
  "paypalrestsdk==1.13.*",
  "paypal-checkout-serversdk==1.0.*",
-  "PyJWT==2.10.*",
+  "PyJWT==2.11.*",
  "phonenumberslite==9.0.*",
-  "Pillow==11.3.*",
+  "Pillow==12.1.*",
  "pretix-plugin-build",
  "protobuf==6.33.*",
  "psycopg2-binary",
  "pycountry",
-  "pycparser==2.23",
+  "pycparser==3.0",
  "pycryptodome==3.23.*",
-  "pypdf==6.3.*",
+  "pypdf==6.5.*",
  "python-bidi==0.6.*",  # Support for Arabic in reportlab
  "python-dateutil==2.9.*",
  "pytz",
  "pytz-deprecation-shim==0.1.*",
  "pyuca",
  "qrcode==8.2",
-  "redis==6.4.*",
+  "redis==7.1.*",
  "reportlab==4.4.*",
  "requests==2.32.*",
-  "sentry-sdk==2.45.*",
+  "sentry-sdk==2.52.*",
  "sepaxml==2.7.*",
  "stripe==7.9.*",
  "text-unidecode==1.*",
  "tlds>=2020041600",
  "tqdm==4.*",
  "ua-parser==1.0.*",
-  "vat_moss_forked==2020.3.20.0.11.0",
  "vobject==0.9.*",
  "webauthn==2.7.*",
  "zeep==4.3.*"
@@ -110,10 +110,10 @@ dev = [
  "aiohttp==3.13.*",
  "coverage",
  "coveralls",
-  "fakeredis==2.32.*",
+  "fakeredis==2.33.*",
  "flake8==7.3.*",
  "freezegun",
-  "isort==6.1.*",
+  "isort==7.0.*",
  "pep8-naming==0.15.*",
  "potypo",
  "pytest-asyncio>=0.24",
@@ -123,7 +123,7 @@ dev = [
  "pytest-mock==3.15.*",
  "pytest-sugar",
  "pytest-xdist==3.8.*",
-  "pytest==8.4.*",
+  "pytest==9.0.*",
  "responses",
 ]

@@ -19,4 +19,4 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
-__version__ = "2025.10.0"
+__version__ = "2026.2.0.dev0"
@@ -795,6 +795,7 @@ class EventSettingsSerializer(SettingsSerializer):
        'invoice_address_asked',
        'invoice_address_required',
        'invoice_address_vatid',
+        'invoice_address_vatid_required_countries',
        'invoice_address_company_required',
        'invoice_address_beneficiary',
        'invoice_address_custom_field',
@@ -805,6 +806,7 @@ class EventSettingsSerializer(SettingsSerializer):
        'invoice_reissue_after_modify',
        'invoice_include_free',
        'invoice_generate',
+        'invoice_generate_only_business',
        'invoice_period',
        'invoice_numbers_consecutive',
        'invoice_numbers_prefix',
@@ -943,6 +945,7 @@ class DeviceEventSettingsSerializer(EventSettingsSerializer):
        'invoice_address_asked',
        'invoice_address_required',
        'invoice_address_vatid',
+        'invoice_address_vatid_required_countries',
        'invoice_address_company_required',
        'invoice_address_beneficiary',
        'invoice_address_custom_field',
@@ -191,7 +191,7 @@ class InvoiceAddressSerializer(I18nAwareModelSerializer):
                                    {"transmission_info": {r: "This field is required for the selected type of invoice transmission."}}
                                )
                    break  # do not call else branch of for loop
-                elif t.exclusive:
+                elif t.is_exclusive(self.context["request"].event, data.get("country"), data.get("is_business")):
                    if t.is_available(self.context["request"].event, data.get("country"), data.get("is_business")):
                        raise ValidationError({
                            "transmission_type": "The transmission type '%s' must be used for this country or address type." % (
@@ -704,6 +704,16 @@ class CheckinListOrderPositionSerializer(OrderPositionSerializer):
        if 'answers.question' in self.context['expand']:
            self.fields['answers'].child.fields['question'] = QuestionSerializer(read_only=True)

+        if 'addons' in self.context['expand']:
+            # Experimental feature, undocumented on purpose for now in case we need to remove it again
+            # for performance reasons
+            subl = CheckinListOrderPositionSerializer(read_only=True, many=True, context={
+                **self.context,
+                'expand': [v for v in self.context['expand'] if v != 'addons'],
+                'pdf_data': False,
+            })
+            self.fields['addons'] = subl
+

 class OrderPaymentTypeField(serializers.Field):
    # TODO: Remove after pretix 2.2
@@ -1601,7 +1611,7 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
                order.sales_channel,
                [
                    (cp.item_id, cp.subevent_id, cp.subevent.date_from if cp.subevent_id else None, cp.price,
-                     bool(cp.addon_to), cp.is_bundled, pos._voucher_discount)
+                     cp.addon_to, cp.is_bundled, pos._voucher_discount)
                    for cp in order_positions
                ]
            )
@@ -1733,6 +1743,7 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
            rounding_mode = self.context["event"].settings.tax_rounding
        changed = apply_rounding(
            rounding_mode,
+            ia,
            self.context["event"].currency,
            [*pos_map.values(), *fees]
        )
@@ -33,7 +33,7 @@ from pretix.api.serializers.order import (
    OrderFeeCreateSerializer, OrderPositionCreateSerializer,
 )
 from pretix.base.models import ItemVariation, Order, OrderFee, OrderPosition
-from pretix.base.services.orders import OrderError
+from pretix.base.services.orders import OrderChangeManager, OrderError
 from pretix.base.settings import COUNTRIES_WITH_STATE_IN_ADDRESS

 logger = logging.getLogger(__name__)
@@ -82,11 +82,11 @@ class OrderPositionCreateForExistingOrderSerializer(OrderPositionCreateSerialize
        return data

    def create(self, validated_data):
-        ocm = self.context['ocm']
+        ocm: OrderChangeManager = self.context['ocm']
        check_quotas = self.context.get('check_quotas', True)

        try:
-            ocm.add_position(
+            new_position = ocm.add_position(
                item=validated_data['item'],
                variation=validated_data.get('variation'),
                price=validated_data.get('price'),
@@ -98,7 +98,7 @@ class OrderPositionCreateForExistingOrderSerializer(OrderPositionCreateSerialize
            )
            if self.context.get('commit', True):
                ocm.commit(check_quotas=check_quotas)
-                return validated_data['order'].positions.order_by('-positionid').first()
+                return new_position.position
            else:
                return OrderPosition()  # fake to appease DRF
        except OrderError as e:
@@ -131,7 +131,7 @@ class OrderFeeCreateForExistingOrderSerializer(OrderFeeCreateSerializer):
        return data

    def create(self, validated_data):
-        ocm = self.context['ocm']
+        ocm: OrderChangeManager = self.context['ocm']

        try:
            f = OrderFee(
@@ -146,7 +146,7 @@ class OrderFeeCreateForExistingOrderSerializer(OrderFeeCreateSerializer):
            ocm.add_fee(f)
            if self.context.get('commit', True):
                ocm.commit()
-                return validated_data['order'].fees.order_by('-pk').first()
+                return f
            else:
                return OrderFee()  # fake to appease DRF
        except OrderError as e:
@@ -310,7 +310,7 @@ class OrderPositionChangeSerializer(serializers.ModelSerializer):
        return data

    def update(self, instance, validated_data):
-        ocm = self.context['ocm']
+        ocm: OrderChangeManager = self.context['ocm']
        check_quotas = self.context.get('check_quotas', True)
        current_seat = {'seat_guid': instance.seat.seat_guid} if instance.seat else None
        item = validated_data.get('item', instance.item)
@@ -399,7 +399,7 @@ class OrderFeeChangeSerializer(serializers.ModelSerializer):
        )

    def update(self, instance, validated_data):
-        ocm = self.context['ocm']
+        ocm: OrderChangeManager = self.context['ocm']
        value = validated_data.get('value', instance.value)

        try:
@@ -49,7 +49,7 @@ from pretix.base.plugins import (
    PLUGIN_LEVEL_EVENT, PLUGIN_LEVEL_EVENT_ORGANIZER_HYBRID,
    PLUGIN_LEVEL_ORGANIZER,
 )
-from pretix.base.services.mail import SendMailException, mail
+from pretix.base.services.mail import mail
 from pretix.base.settings import validate_organizer_settings
 from pretix.helpers.urls import build_absolute_uri as build_global_uri
 from pretix.multidomain.urlreverse import build_absolute_uri
@@ -363,24 +363,21 @@ class TeamInviteSerializer(serializers.ModelSerializer):
        )

    def _send_invite(self, instance):
-        try:
-            mail(
-                instance.email,
-                _('pretix account invitation'),
-                'pretixcontrol/email/invitation.txt',
-                {
-                    'user': self,
-                    'organizer': self.context['organizer'].name,
-                    'team': instance.team.name,
-                    'url': build_global_uri('control:auth.invite', kwargs={
-                        'token': instance.token
-                    })
-                },
-                event=None,
-                locale=get_language_without_region()  # TODO: expose?
-            )
-        except SendMailException:
-            pass  # Already logged
+        mail(
+            instance.email,
+            _('pretix account invitation'),
+            'pretixcontrol/email/invitation.txt',
+            {
+                'user': self,
+                'organizer': self.context['organizer'].name,
+                'team': instance.team.name,
+                'url': build_global_uri('control:auth.invite', kwargs={
+                    'token': instance.token
+                })
+            },
+            event=None,
+            locale=get_language_without_region()  # TODO: expose?
+        )

    def create(self, validated_data):
        if 'email' in validated_data:
@@ -443,6 +440,7 @@ class OrganizerSettingsSerializer(SettingsSerializer):
        'customer_accounts',
        'customer_accounts_native',
        'customer_accounts_link_by_email',
+        'customer_accounts_require_login_for_order_access',
        'invoice_regenerate_allowed',
        'contact_mail',
        'imprint_url',
@@ -381,15 +381,21 @@ def _checkin_list_position_queryset(checkinlists, ignore_status=False, ignore_pr

    qs = qs.filter(reduce(operator.or_, lists_qs))

+    prefetch_related = [
+        Prefetch(
+            lookup='checkins',
+            queryset=Checkin.objects.filter(list_id__in=[cl.pk for cl in checkinlists]).select_related('device')
+        ),
+        Prefetch('print_logs', queryset=PrintLog.objects.select_related('device')),
+        'answers', 'answers__options', 'answers__question',
+    ]
+    select_related = [
+        'item', 'variation', 'order', 'addon_to', 'order__invoice_address', 'order', 'seat'
+    ]
+
    if pdf_data:
        qs = qs.prefetch_related(
-            Prefetch(
-                lookup='checkins',
-                queryset=Checkin.objects.filter(list_id__in=[cl.pk for cl in checkinlists]).select_related('device')
-            ),
-            Prefetch('print_logs', queryset=PrintLog.objects.select_related('device')),
-            'answers', 'answers__options', 'answers__question',
-            Prefetch('addons', OrderPosition.objects.select_related('item', 'variation')),
+            # Don't add to list, we don't want to propagate to addons
            Prefetch('order', Order.objects.select_related('invoice_address').prefetch_related(
                Prefetch(
                    'event',
@@ -404,32 +410,39 @@ def _checkin_list_position_queryset(checkinlists, ignore_status=False, ignore_pr
                    )
                )
            ))
-        ).select_related(
-            'item', 'variation', 'item__category', 'addon_to', 'order', 'order__invoice_address', 'seat'
        )
-    else:
-        qs = qs.prefetch_related(
-            Prefetch(
-                lookup='checkins',
-                queryset=Checkin.objects.filter(list_id__in=[cl.pk for cl in checkinlists]).select_related('device')
-            ),
-            Prefetch('print_logs', queryset=PrintLog.objects.select_related('device')),
-            'answers', 'answers__options', 'answers__question',
-            Prefetch('addons', OrderPosition.objects.select_related('item', 'variation'))
-        ).select_related('item', 'variation', 'order', 'addon_to', 'order__invoice_address', 'order', 'seat')

    if expand and 'subevent' in expand:
-        qs = qs.prefetch_related(
+        prefetch_related += [
            'subevent', 'subevent__event', 'subevent__subeventitem_set', 'subevent__subeventitemvariation_set',
            'subevent__seat_category_mappings', 'subevent__meta_values'
-        )
+        ]

    if expand and 'item' in expand:
-        qs = qs.prefetch_related('item', 'item__addons', 'item__bundles', 'item__meta_values',
-                                 'item__variations').select_related('item__tax_rule')
+        prefetch_related += [
+            'item', 'item__addons', 'item__bundles', 'item__meta_values',
+            'item__variations',
+        ]
+        select_related.append('item__tax_rule')

    if expand and 'variation' in expand:
-        qs = qs.prefetch_related('variation', 'variation__meta_values')
+        prefetch_related += [
+            'variation', 'variation__meta_values',
+        ]
+
+    if expand and 'addons' in expand:
+        prefetch_related += [
+            Prefetch('addons', OrderPosition.objects.prefetch_related(*prefetch_related).select_related(*select_related)),
+        ]
+    else:
+        prefetch_related += [
+            Prefetch('addons', OrderPosition.objects.select_related('item', 'variation'))
+        ]
+
+    if pdf_data:
+        select_related.remove("order")  # Don't need it twice on this queryset
+
+    qs = qs.prefetch_related(*prefetch_related).select_related(*select_related)

    return qs

@@ -966,6 +979,7 @@ class CheckinRPCSearchView(ListAPIView):
    def get_serializer_context(self):
        ctx = super().get_serializer_context()
        ctx['expand'] = self.request.query_params.getlist('expand')
+        ctx['organizer'] = self.request.organizer
        ctx['pdf_data'] = False
        return ctx

@@ -74,6 +74,11 @@ class ExportersMixin:
    @action(detail=True, methods=['GET'], url_name='download', url_path='download/(?P<asyncid>[^/]+)/(?P<cfid>[^/]+)')
    def download(self, *args, **kwargs):
        cf = get_object_or_404(CachedFile, id=kwargs['cfid'])
+        if not cf.allowed_for_session(self.request, "exporters-api"):
+            return Response(
+                {'status': 'failed', 'message': 'Unknown file ID or export failed'},
+                status=status.HTTP_410_GONE
+            )
        if cf.file:
            resp = ChunkBasedFileResponse(cf.file.file, content_type=cf.type)
            resp['Content-Disposition'] = 'attachment; filename="{}"'.format(cf.filename).encode("ascii", "ignore")
@@ -109,7 +114,8 @@ class ExportersMixin:
        serializer = JobRunSerializer(exporter=instance, data=self.request.data, **self.get_serializer_kwargs())
        serializer.is_valid(raise_exception=True)

-        cf = CachedFile(web_download=False)
+        cf = CachedFile(web_download=True)
+        cf.bind_to_session(self.request, "exporters-api")
        cf.date = now()
        cf.expires = now() + timedelta(hours=24)
        cf.save()
@@ -106,7 +106,7 @@ class ItemViewSet(ConditionalListView, viewsets.ModelViewSet):
            'variations', 'addons', 'bundles', 'meta_values', 'meta_values__property',
            'variations__meta_values', 'variations__meta_values__property',
            'require_membership_types', 'variations__require_membership_types',
-            'limit_sales_channels', 'variations__limit_sales_channels',
+            'limit_sales_channels', 'variations__limit_sales_channels', 'program_times'
        ).all()

    def perform_create(self, serializer):
@@ -567,7 +567,7 @@ class QuotaViewSet(ConditionalListView, viewsets.ModelViewSet):
    write_permission = 'can_change_items'

    def get_queryset(self):
-        return self.request.event.quotas.all()
+        return self.request.event.quotas.select_related('subevent').prefetch_related('items', 'variations').all()

    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset()).distinct()
@@ -90,7 +90,6 @@ from pretix.base.services.invoices import (
    generate_cancellation, generate_invoice, invoice_pdf, invoice_qualified,
    regenerate_invoice, transmit_invoice,
 )
-from pretix.base.services.mail import SendMailException
 from pretix.base.services.orders import (
    OrderChangeManager, OrderError, _order_placed_email,
    _order_placed_email_attendee, approve_order, cancel_order, deny_order,
@@ -439,8 +438,6 @@ class EventOrderViewSet(OrderViewSetMixin, viewsets.ModelViewSet):
                return Response({'detail': str(e)}, status=status.HTTP_400_BAD_REQUEST)
            except PaymentException as e:
                return Response({'detail': str(e)}, status=status.HTTP_400_BAD_REQUEST)
-            except SendMailException:
-                pass

            return self.retrieve(request, [], **kwargs)
        return Response(
@@ -634,10 +631,7 @@ class EventOrderViewSet(OrderViewSetMixin, viewsets.ModelViewSet):
        order = self.get_object()
        if not order.email:
            return Response({'detail': 'There is no email address associated with this order.'}, status=status.HTTP_400_BAD_REQUEST)
-        try:
-            order.resend_link(user=self.request.user, auth=self.request.auth)
-        except SendMailException:
-            return Response({'detail': _('There was an error sending the mail. Please try again later.')}, status=status.HTTP_503_SERVICE_UNAVAILABLE)
+        order.resend_link(user=self.request.user, auth=self.request.auth)

        return Response(
            status=status.HTTP_204_NO_CONTENT
@@ -1616,8 +1610,6 @@ class PaymentViewSet(CreateModelMixin, viewsets.ReadOnlyModelViewSet):
                    )
                except Quota.QuotaExceededException:
                    pass
-                except SendMailException:
-                    pass

            serializer = OrderPaymentSerializer(r, context=serializer.context)

@@ -1655,8 +1647,6 @@ class PaymentViewSet(CreateModelMixin, viewsets.ReadOnlyModelViewSet):
            return Response({'detail': str(e)}, status=status.HTTP_400_BAD_REQUEST)
        except PaymentException as e:
            return Response({'detail': str(e)}, status=status.HTTP_400_BAD_REQUEST)
-        except SendMailException:
-            pass
        return self.retrieve(request, [], **kwargs)

    @action(detail=True, methods=['POST'])
@@ -2031,7 +2021,7 @@ class InvoiceViewSet(viewsets.ReadOnlyModelViewSet):
        else:
            order = Order.objects.select_for_update(of=OF_SELF).get(pk=inv.order_id)
            c = generate_cancellation(inv)
-            if inv.order.status != Order.STATUS_CANCELED:
+            if invoice_qualified(order):
                inv = generate_invoice(order)
            else:
                inv = c
@@ -249,12 +249,17 @@ class GiftCardViewSet(viewsets.ModelViewSet):
    def perform_create(self, serializer):
        value = serializer.validated_data.pop('value')
        inst = serializer.save(issuer=self.request.organizer)
-        inst.transactions.create(value=value, acceptor=self.request.organizer)
        inst.log_action(
-            'pretix.giftcards.transaction.manual',
+            action='pretix.giftcards.created',
            user=self.request.user,
            auth=self.request.auth,
-            data=merge_dicts(self.request.data, {'id': inst.pk})
+        )
+        inst.transactions.create(value=value, acceptor=self.request.organizer)
+        inst.log_action(
+            action='pretix.giftcards.transaction.manual',
+            user=self.request.user,
+            auth=self.request.auth,
+            data=merge_dicts(self.request.data, {'id': inst.pk, 'acceptor_id': self.request.organizer.id})
        )

    @transaction.atomic()
@@ -269,7 +274,7 @@ class GiftCardViewSet(viewsets.ModelViewSet):
            inst = serializer.save(secret=serializer.instance.secret, currency=serializer.instance.currency,
                                   testmode=serializer.instance.testmode)
            inst.log_action(
-                'pretix.giftcards.modified',
+                action='pretix.giftcards.modified',
                user=self.request.user,
                auth=self.request.auth,
                data=self.request.data,
@@ -282,10 +287,10 @@ class GiftCardViewSet(viewsets.ModelViewSet):
            diff = value - old_value
            inst.transactions.create(value=diff, acceptor=self.request.organizer)
            inst.log_action(
-                'pretix.giftcards.transaction.manual',
+                action='pretix.giftcards.transaction.manual',
                user=self.request.user,
                auth=self.request.auth,
-                data={'value': diff}
+                data={'value': diff, 'acceptor_id': self.request.organizer.id}
            )

        return inst
@@ -309,10 +314,14 @@ class GiftCardViewSet(viewsets.ModelViewSet):
            }, status=status.HTTP_409_CONFLICT)
        gc.transactions.create(value=value, text=text, info=info, acceptor=self.request.organizer)
        gc.log_action(
-            'pretix.giftcards.transaction.manual',
+            action='pretix.giftcards.transaction.manual',
            user=self.request.user,
            auth=self.request.auth,
-            data={'value': value, 'text': text}
+            data={
+                'value': value,
+                'text': text,
+                'acceptor_id': self.request.organizer.id
+            }
        )
        return Response(GiftCardSerializer(gc, context=self.get_serializer_context()).data, status=status.HTTP_200_OK)

@@ -721,7 +730,7 @@ class MembershipViewSet(viewsets.ModelViewSet):
    def get_queryset(self):
        return Membership.objects.filter(
            customer__organizer=self.request.organizer
-        )
+        ).select_related('customer')

    def get_serializer_context(self):
        ctx = super().get_serializer_context()
@@ -19,6 +19,7 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
+
 from django.db import transaction
 from django.db.models import F, Q
 from django.utils.timezone import now
@@ -64,8 +65,13 @@ class VoucherViewSet(viewsets.ModelViewSet):
    permission = 'can_view_vouchers'
    write_permission = 'can_change_vouchers'

+    @scopes_disabled()  # we have an event check here, and we can save some performance on subqueries
    def get_queryset(self):
-        return self.request.event.vouchers.select_related('seat').all()
+        return Voucher.annotate_budget_used(
+            self.request.event.vouchers
+        ).select_related(
+            'item', 'quota', 'seat', 'variation'
+        )

    @transaction.atomic()
    def create(self, request, *args, **kwargs):
@@ -43,6 +43,7 @@ from pretix.base.services.tasks import ProfiledTask, TransactionAwareTask
 from pretix.base.signals import periodic_task
 from pretix.celery_app import app
 from pretix.helpers import OF_SELF
+from pretix.helpers.celery import get_task_priority

 logger = logging.getLogger(__name__)
 _ALL_EVENTS = None
@@ -173,6 +174,35 @@ class ParametrizedEventWebhookEvent(ParametrizedWebhookEvent):
        }


+class ParametrizedGiftcardWebhookEvent(ParametrizedWebhookEvent):
+    def build_payload(self, logentry: LogEntry):
+        giftcard = logentry.content_object
+        if not giftcard:
+            return None
+
+        return {
+            'notification_id': logentry.pk,
+            'issuer_id': logentry.organizer_id,
+            'giftcard': giftcard.pk,
+            'action': logentry.action_type,
+        }
+
+
+class ParametrizedGiftcardTransactionWebhookEvent(ParametrizedWebhookEvent):
+    def build_payload(self, logentry: LogEntry):
+        giftcard = logentry.content_object
+        if not giftcard:
+            return None
+
+        return {
+            'notification_id': logentry.pk,
+            'issuer_id': logentry.organizer_id,
+            'acceptor_id': logentry.parsed_data.get('acceptor_id'),
+            'giftcard': giftcard.pk,
+            'action': logentry.action_type,
+        }
+
+
 class ParametrizedVoucherWebhookEvent(ParametrizedWebhookEvent):

    def build_payload(self, logentry: LogEntry):
@@ -432,6 +462,18 @@ def register_default_webhook_events(sender, **kwargs):
            'pretix.customer.anonymized',
            _('Customer account anonymized'),
        ),
+        ParametrizedGiftcardWebhookEvent(
+            'pretix.giftcards.created',
+            _('Gift card added'),
+        ),
+        ParametrizedGiftcardWebhookEvent(
+            'pretix.giftcards.modified',
+            _('Gift card modified'),
+        ),
+        ParametrizedGiftcardTransactionWebhookEvent(
+            'pretix.giftcards.transaction.*',
+            _('Gift card used in transcation'),
+        )
    )


@@ -474,7 +516,10 @@ def notify_webhooks(logentry_ids: list):
                )

        for wh in webhooks:
-            send_webhook.apply_async(args=(logentry.id, notification_type.action_type, wh.pk))
+            send_webhook.apply_async(
+                args=(logentry.id, notification_type.action_type, wh.pk),
+                priority=get_task_priority("notifications", logentry.organizer_id),
+            )


@app.task(base=ProfiledTask, bind=True, max_retries=5, default_retry_delay=60, acks_late=True, autoretry_for=(DatabaseError,),)
@@ -90,6 +90,7 @@ StaticMapping = namedtuple('StaticMapping', ('id', 'pretix_model', 'external_obj

 class OutboundSyncProvider:
    max_attempts = 5
+    list_field_joiner = ","  # set to None to keep native lists in properties

    def __init__(self, event):
        self.event = event
@@ -281,7 +282,8 @@ class OutboundSyncProvider:
                            'Please update value mapping for field "{field_name}" - option "{val}" not assigned'
                        ).format(field_name=key, val=val)])

-            val = ",".join(val)
+            if self.list_field_joiner:
+                val = self.list_field_joiner.join(val)
        return val

    def get_properties(self, inputs: dict, property_mappings: List[dict]):
@@ -71,15 +71,20 @@ def assign_properties(
    return out


-def _add_to_list(out, field_name, current_value, new_item, list_sep):
-    new_item = str(new_item)
+def _add_to_list(out, field_name, current_value, new_item_input, list_sep):
    if list_sep is not None:
-        new_item = new_item.replace(list_sep, "")
+        new_items = str(new_item_input).split(list_sep)
        current_value = current_value.split(list_sep) if current_value else []
-    elif not isinstance(current_value, (list, tuple)):
-        current_value = [str(current_value)]
-    if new_item not in current_value:
-        new_list = current_value + [new_item]
+    else:
+        new_items = [str(new_item_input)]
+        if not isinstance(current_value, (list, tuple)):
+            current_value = [str(current_value)]
+
+    new_list = list(current_value)
+    for new_item in new_items:
+        if new_item not in current_value:
+            new_list.append(new_item)
+    if new_list != current_value:
        if list_sep is not None:
            new_list = list_sep.join(new_list)
        out[field_name] = new_list
@@ -39,7 +39,7 @@ from pretix.base.templatetags.rich_text import (
    DEFAULT_CALLBACKS, EMAIL_RE, URL_RE, abslink_callback,
    markdown_compile_email, truelink_callback,
 )
-from pretix.helpers.format import SafeFormatter, format_map
+from pretix.helpers.format import FormattedString, SafeFormatter, format_map

 from pretix.base.services.placeholders import (  # noqa
    get_available_placeholders, PlaceholderContext
@@ -141,6 +141,7 @@ class TemplateBasedMailRenderer(BaseHTMLMailRenderer):
        return markdown_compile_email(plaintext, context=context)

    def render(self, plain_body: str, plain_signature: str, subject: str, order, position, context) -> str:
+        apply_format_map = not isinstance(plain_body, FormattedString)
        body_md = self.compile_markdown(plain_body, context)
        if context:
            linker = bleach.Linker(
@@ -149,12 +150,13 @@ class TemplateBasedMailRenderer(BaseHTMLMailRenderer):
                callbacks=DEFAULT_CALLBACKS + [truelink_callback, abslink_callback],
                parse_email=True
            )
-            body_md = format_map(
-                body_md,
-                context=context,
-                mode=SafeFormatter.MODE_RICH_TO_HTML,
-                linkifier=linker
-            )
+            if apply_format_map:
+                body_md = format_map(
+                    body_md,
+                    context=context,
+                    mode=SafeFormatter.MODE_RICH_TO_HTML,
+                    linkifier=linker
+                )
        htmlctx = {
            'site': settings.PRETIX_INSTANCE_NAME,
            'site_url': settings.SITE_URL,
@@ -39,8 +39,8 @@ from zoneinfo import ZoneInfo
 from django import forms
 from django.conf import settings
 from django.db.models import (
-    Case, CharField, Count, DateTimeField, F, IntegerField, Max, Min, OuterRef,
-    Q, Subquery, Sum, When,
+    Case, CharField, Count, DateTimeField, Exists, F, IntegerField, Max, Min,
+    OuterRef, Q, Subquery, Sum, When,
 )
 from django.db.models.functions import Coalesce
 from django.dispatch import receiver
@@ -144,6 +144,18 @@ class OrderListExporter(MultiSheetListExporter):
        d = OrderedDict(d)
        if not self.is_multievent and not self.event.has_subevents:
            del d['event_date_range']
+        if not self.is_multievent:
+            d["items"] = forms.ModelMultipleChoiceField(
+                label=_("Products"),
+                queryset=self.event.items.all(),
+                widget=forms.CheckboxSelectMultiple(
+                    attrs={"class": "scrolling-multiple-choice"}
+                ),
+                help_text=_("If none are selected, all products are included. Orders are included if they contain "
+                            "at least one position of this product. The order totals etc. still include all products "
+                            "contained in the order."),
+                required=False,
+            )
        return d

    def _get_all_payment_methods(self, qs):
@@ -249,6 +261,14 @@ class OrderListExporter(MultiSheetListExporter):
            pcnt=Subquery(s, output_field=IntegerField())
        ).select_related('invoice_address', 'customer')

+        if form_data.get('items'):
+            qs = qs.filter(
+                Exists(OrderPosition.all.filter(
+                    order=OuterRef('pk'),
+                    item__in=form_data["items"]
+                ))
+            )
+
        qs = self._date_filter(qs, form_data, rel='')

        if form_data['paid_only']:
@@ -364,7 +384,7 @@ class OrderListExporter(MultiSheetListExporter):
                    order.invoice_address.city,
                    order.invoice_address.country if order.invoice_address.country else
                    order.invoice_address.country_old,
-                    order.invoice_address.state,
+                    order.invoice_address.state_for_address,
                    order.invoice_address.custom_field,
                    order.invoice_address.vat_id,
                ]
@@ -440,6 +460,14 @@ class OrderListExporter(MultiSheetListExporter):
        if form_data['paid_only']:
            qs = qs.filter(order__status=Order.STATUS_PAID, canceled=False)

+        if form_data.get('items'):
+            qs = qs.filter(
+                Exists(OrderPosition.all.filter(
+                    order=OuterRef('order'),
+                    item__in=form_data["items"]
+                ))
+            )
+
        qs = self._date_filter(qs, form_data, rel='order__')
        return qs

@@ -515,7 +543,7 @@ class OrderListExporter(MultiSheetListExporter):
                    order.invoice_address.city,
                    order.invoice_address.country if order.invoice_address.country else
                    order.invoice_address.country_old,
-                    order.invoice_address.state,
+                    order.invoice_address.state_for_address,
                    order.invoice_address.vat_id,
                ]
            except InvoiceAddress.DoesNotExist:
@@ -535,6 +563,11 @@ class OrderListExporter(MultiSheetListExporter):
        if form_data['paid_only']:
            qs = qs.filter(order__status=Order.STATUS_PAID, canceled=False)

+        if form_data.get('items'):
+            qs = qs.filter(
+                item__in=form_data["items"]
+            )
+
        qs = self._date_filter(qs, form_data, rel='order__')
        return qs

@@ -617,6 +650,7 @@ class OrderListExporter(MultiSheetListExporter):
            _('Country'),
            pgettext('address', 'State'),
            _('Voucher'),
+            _('Voucher budget usage'),
            _('Pseudonymization ID'),
            _('Ticket secret'),
            _('Seat ID'),
@@ -732,8 +766,9 @@ class OrderListExporter(MultiSheetListExporter):
                    op.zipcode or '',
                    op.city or '',
                    op.country if op.country else '',
-                    op.state or '',
+                    op.state_for_address or '',
                    op.voucher.code if op.voucher else '',
+                    op.voucher_budget_use if op.voucher_budget_use else '',
                    op.pseudonymization_id,
                    op.secret,
                ]
@@ -797,7 +832,7 @@ class OrderListExporter(MultiSheetListExporter):
                        order.invoice_address.city,
                        order.invoice_address.country if order.invoice_address.country else
                        order.invoice_address.country_old,
-                        order.invoice_address.state,
+                        order.invoice_address.state_for_address,
                        order.invoice_address.vat_id,
                    ]
                except InvoiceAddress.DoesNotExist:
@@ -66,8 +66,10 @@ from geoip2.errors import AddressNotFoundError
 from phonenumber_field.formfields import PhoneNumberField
 from phonenumber_field.phonenumber import PhoneNumber
 from phonenumber_field.widgets import PhoneNumberPrefixWidget
-from phonenumbers import NumberParseException, national_significant_number
-from phonenumbers.data import _COUNTRY_CODE_TO_REGION_CODE
+from phonenumbers import (
+    COUNTRY_CODE_TO_REGION_CODE, REGION_CODE_FOR_NON_GEO_ENTITY,
+    NumberParseException, national_significant_number,
+)
 from PIL import ImageOps

 from pretix.base.forms.widgets import (
@@ -83,7 +85,7 @@ from pretix.base.invoicing.transmission import (
 from pretix.base.models import InvoiceAddress, Item, Question, QuestionOption
 from pretix.base.models.tax import ask_for_vat_id
 from pretix.base.services.tax import (
-    VATIDFinalError, VATIDTemporaryError, validate_vat_id,
+    VATIDFinalError, VATIDTemporaryError, normalize_vat_id, validate_vat_id,
 )
 from pretix.base.settings import (
    COUNTRIES_WITH_STATE_IN_ADDRESS, COUNTRY_STATE_LABEL,
@@ -305,7 +307,9 @@ class WrappedPhonePrefixSelect(Select):
        choices = [("", "---------")]

        if initial:
-            for prefix, values in _COUNTRY_CODE_TO_REGION_CODE.items():
+            for prefix, values in COUNTRY_CODE_TO_REGION_CODE.items():
+                if all(v == REGION_CODE_FOR_NON_GEO_ENTITY for v in values):
+                    continue
                if initial in values:
                    self.initial = "+%d" % prefix
                    break
@@ -437,7 +441,9 @@ def guess_phone_prefix_from_request(request, event):


 def get_phone_prefix(country):
-    for prefix, values in _COUNTRY_CODE_TO_REGION_CODE.items():
+    if country == REGION_CODE_FOR_NON_GEO_ENTITY:
+        return None
+    for prefix, values in COUNTRY_CODE_TO_REGION_CODE.items():
        if country in values:
            return prefix
    return None
@@ -884,18 +890,18 @@ class BaseQuestionsForm(forms.Form):
                if not help_text:
                    if q.valid_date_min and q.valid_date_max:
                        help_text = format_lazy(
-                            'Please enter a date between {min} and {max}.',
+                            _('Please enter a date between {min} and {max}.'),
                            min=date_format(q.valid_date_min, "SHORT_DATE_FORMAT"),
                            max=date_format(q.valid_date_max, "SHORT_DATE_FORMAT"),
                        )
                    elif q.valid_date_min:
                        help_text = format_lazy(
-                            'Please enter a date no earlier than {min}.',
+                            _('Please enter a date no earlier than {min}.'),
                            min=date_format(q.valid_date_min, "SHORT_DATE_FORMAT"),
                        )
                    elif q.valid_date_max:
                        help_text = format_lazy(
-                            'Please enter a date no later than {max}.',
+                            _('Please enter a date no later than {max}.'),
                            max=date_format(q.valid_date_max, "SHORT_DATE_FORMAT"),
                        )
                if initial and initial.answer:
@@ -933,18 +939,18 @@ class BaseQuestionsForm(forms.Form):
                if not help_text:
                    if q.valid_datetime_min and q.valid_datetime_max:
                        help_text = format_lazy(
-                            'Please enter a date and time between {min} and {max}.',
+                            _('Please enter a date and time between {min} and {max}.'),
                            min=date_format(q.valid_datetime_min, "SHORT_DATETIME_FORMAT"),
                            max=date_format(q.valid_datetime_max, "SHORT_DATETIME_FORMAT"),
                        )
                    elif q.valid_datetime_min:
                        help_text = format_lazy(
-                            'Please enter a date and time no earlier than {min}.',
+                            _('Please enter a date and time no earlier than {min}.'),
                            min=date_format(q.valid_datetime_min, "SHORT_DATETIME_FORMAT"),
                        )
                    elif q.valid_datetime_max:
                        help_text = format_lazy(
-                            'Please enter a date and time no later than {max}.',
+                            _('Please enter a date and time no later than {max}.'),
                            max=date_format(q.valid_datetime_max, "SHORT_DATETIME_FORMAT"),
                        )

@@ -1165,13 +1171,11 @@ class BaseInvoiceAddressForm(forms.ModelForm):
            self.fields['vat_id'].help_text = '<br/>'.join([
                str(_('Optional, but depending on the country you reside in we might need to charge you '
                      'additional taxes if you do not enter it.')),
-                str(_('If you are registered in Switzerland, you can enter your UID instead.')),
            ])
        else:
            self.fields['vat_id'].help_text = '<br/>'.join([
                str(_('Optional, but it might be required for you to claim tax benefits on your invoice '
                      'depending on your and the seller’s country of residence.')),
-                str(_('If you are registered in Switzerland, you can enter your UID instead.')),
            ])

        transmission_type_choices = [
@@ -1358,13 +1362,24 @@ class BaseInvoiceAddressForm(forms.ModelForm):
                                            "transmission method.")}
                )

+        vat_id_applicable = (
+            'vat_id' in self.fields and
+            data.get('is_business') and
+            ask_for_vat_id(data.get('country'))
+        )
+        vat_id_required = vat_id_applicable and str(data.get('country')) in self.event.settings.invoice_address_vatid_required_countries
+        if vat_id_required and not data.get('vat_id'):
+            raise ValidationError({
+                "vat_id": _("This field is required.")
+            })
+
        if self.validate_vat_id and self.instance.vat_id_validated and 'vat_id' not in self.changed_data:
-            pass
-        elif self.validate_vat_id and data.get('is_business') and ask_for_vat_id(data.get('country')) and data.get('vat_id'):
+            pass  # Skip re-validation if it is validated
+        elif self.validate_vat_id and vat_id_applicable:
            try:
                normalized_id = validate_vat_id(data.get('vat_id'), str(data.get('country')))
                self.instance.vat_id_validated = True
-                self.instance.vat_id = normalized_id
+                self.instance.vat_id = data['vat_id'] = normalized_id
            except VATIDFinalError as e:
                if self.all_optional:
                    self.instance.vat_id_validated = False
@@ -1372,6 +1387,9 @@ class BaseInvoiceAddressForm(forms.ModelForm):
                else:
                    raise ValidationError({"vat_id": e.message})
            except VATIDTemporaryError as e:
+                # We couldn't check it online, but we can still normalize it
+                normalized_id = normalize_vat_id(data.get('vat_id'), str(data.get('country')))
+                self.instance.vat_id = data['vat_id'] = normalized_id
                self.instance.vat_id_validated = False
                if self.request and self.vat_warning:
                    messages.warning(self.request, e.message)
@@ -1399,7 +1417,7 @@ class BaseInvoiceAddressForm(forms.ModelForm):

                self.instance.transmission_type = transmission_type.identifier
                self.instance.transmission_info = transmission_type.form_data_to_transmission_info(data)
-            elif transmission_type.exclusive:
+            elif transmission_type.is_exclusive(self.event, data.get("country"), data.get("is_business")):
                if transmission_type.is_available(self.event, data.get("country"), data.get("is_business")):
                    raise ValidationError({
                        "transmission_type": "The transmission type '%s' must be used for this country or address type." % (
@@ -34,14 +34,13 @@

 from contextlib import contextmanager

+from asgiref.local import Local
 from babel import localedata
 from django.conf import settings
 from django.utils import translation
 from django.utils.formats import date_format, number_format
 from django.utils.translation import gettext

-from pretix.base.templatetags.money import money_filter
-
 from i18nfield.fields import (  # noqa
    I18nCharField, I18nTextarea, I18nTextField, I18nTextInput,
 )
@@ -51,6 +50,9 @@ from i18nfield.strings import LazyI18nString  # noqa
 from i18nfield.utils import I18nJSONEncoder  # noqa


+_active_region = Local()
+
+
 class LazyDate:
    def __init__(self, value):
        self.value = value
@@ -86,6 +88,8 @@ class LazyCurrencyNumber:
        return self.__str__()

    def __str__(self):
+        from pretix.base.templatetags.money import money_filter
+
        return money_filter(self.value, self.currency)


@@ -105,14 +109,41 @@ ALLOWED_LANGUAGES = dict(settings.LANGUAGES)


 def get_babel_locale():
-    babel_locale = 'en'
-    # Babel, and therefore django-phonenumberfield, do not support our custom locales such das de_Informal
-    if translation.get_language():
-        if localedata.exists(translation.get_language()):
-            babel_locale = translation.get_language()
-        elif localedata.exists(translation.get_language()[:2]):
-            babel_locale = translation.get_language()[:2]
-    return babel_locale
+    # Babel, and therefore also django-phonenumberfield, do not support our custom locales such das de_Informal
+    # Also, this returns best-effort region information for number formatting etc
+    current_language = translation.get_language()
+    current_region = getattr(_active_region, "value", None)
+
+    # Babel only accepts locales that exist on the system. We try combinations in the following order:
+    # language-languageversion-region
+    # language-region
+    # language-languageversion
+    # language
+    # fallback to system default
+    # fallback to english
+
+    try_locales = []
+    if current_language:
+        if "-" in current_language:
+            lng_parts = current_language.split("-")
+            if current_region:
+                try_locales.append(f"{lng_parts[0]}_{lng_parts[1].title()}_{current_region.upper()}")
+                try_locales.append(f"{lng_parts[0]}_{current_region.upper()}")
+            try_locales.append(f"{lng_parts[0]}_{lng_parts[1].upper()}")
+            try_locales.append(f"{lng_parts[0]}_{lng_parts[1].title()}")
+            try_locales.append(f"{lng_parts[0]}")
+        else:
+            if current_region:
+                try_locales.append(f"{current_language}_{current_region.upper()}")
+            try_locales.append(f"{current_language}")
+
+    try_locales.append(settings.LANGUAGE_CODE)
+
+    for locale in try_locales:
+        if localedata.exists(locale):
+            return localedata.normalize_locale(locale)
+
+    return "en"


 def get_language_without_region(lng=None):
@@ -132,6 +163,10 @@ def get_language_without_region(lng=None):
    return lng


+def set_region(region):
+    _active_region.value = region
+
+
@contextmanager
 def language(lng, region=None):
    """
@@ -143,15 +178,18 @@ def language(lng, region=None):
    formatting. If you pass a ``lng`` that already contains a region, e.g. ``pt-br``, the ``region``
    attribute will be ignored.
    """
-    _lng = translation.get_language()
+    lng_before = translation.get_language()
+    region_before = getattr(_active_region, "value", None)
    lng = lng or settings.LANGUAGE_CODE
    if '-' not in lng and region:
        lng += '-' + region.lower()
    translation.activate(lng)
+    _active_region.value = region
    try:
        yield
    finally:
-        translation.activate(_lng)
+        translation.activate(lng_before)
+        _active_region.value = region_before


 class LazyLocaleException(Exception):
@@ -33,7 +33,7 @@ from pretix.base.invoicing.transmission import (
    transmission_types,
 )
 from pretix.base.models import Invoice, InvoiceAddress
-from pretix.base.services.mail import SendMailException, mail, render_mail
+from pretix.base.services.mail import mail, render_mail
 from pretix.helpers.format import format_map


@@ -133,41 +133,37 @@ class EmailTransmissionProvider(TransmissionProvider):
            template = invoice.order.event.settings.get('mail_text_order_invoice', as_type=LazyI18nString)
            subject = invoice.order.event.settings.get('mail_subject_order_invoice', as_type=LazyI18nString)

-            try:
-                # Do not set to completed because that is done by the email sending task
-                subject = format_map(subject, context)
-                email_content = render_mail(template, context)
-                mail(
-                    [recipient],
-                    subject,
-                    template,
-                    context=context,
-                    event=invoice.order.event,
-                    locale=invoice.order.locale,
-                    order=invoice.order,
-                    invoices=[invoice],
-                    attach_tickets=False,
-                    auto_email=True,
-                    attach_ical=False,
-                    plain_text_only=True,
-                    no_order_links=True,
-                )
-            except SendMailException:
-                raise
-            else:
-                invoice.order.log_action(
-                    'pretix.event.order.email.invoice',
-                    user=None,
-                    auth=None,
-                    data={
-                        'subject': subject,
-                        'message': email_content,
-                        'position': None,
-                        'recipient': recipient,
-                        'invoices': [invoice.pk],
-                        'attach_tickets': False,
-                        'attach_ical': False,
-                        'attach_other_files': [],
-                        'attach_cached_files': [],
-                    }
-                )
+            # Do not set to completed because that is done by the email sending task
+            subject = format_map(subject, context)
+            email_content = render_mail(template, context)
+            mail(
+                [recipient],
+                subject,
+                template,
+                context=context,
+                event=invoice.order.event,
+                locale=invoice.order.locale,
+                order=invoice.order,
+                invoices=[invoice],
+                attach_tickets=False,
+                auto_email=True,
+                attach_ical=False,
+                plain_text_only=True,
+                no_order_links=True,
+            )
+            invoice.order.log_action(
+                'pretix.event.order.email.invoice',
+                user=None,
+                auth=None,
+                data={
+                    'subject': subject,
+                    'message': email_content,
+                    'position': None,
+                    'recipient': recipient,
+                    'invoices': [invoice.pk],
+                    'attach_tickets': False,
+                    'attach_ical': False,
+                    'attach_other_files': [],
+                    'attach_cached_files': [],
+                }
+            )
@@ -36,9 +36,11 @@ class ItalianSdITransmissionType(TransmissionType):
    identifier = "it_sdi"
    verbose_name = pgettext_lazy("italian_invoice", "Italian Exchange System (SdI)")
    public_name = pgettext_lazy("italian_invoice", "Exchange System (SdI)")
-    exclusive = True
    enforce_transmission = True

+    def is_exclusive(self, event, country: Country, is_business: bool) -> bool:
+        return str(country) == "IT"
+
    def is_available(self, event, country: Country, is_business: bool):
        return str(country) == "IT" and super().is_available(event, country, is_business)

@@ -32,7 +32,6 @@ from itertools import groupby
 from typing import Tuple

 import bleach
-import vat_moss.exchange_rates
 from bidi import get_display
 from django.contrib.staticfiles import finders
 from django.db.models import Sum
@@ -47,7 +46,6 @@ from reportlab.lib.styles import ParagraphStyle, StyleSheet1
 from reportlab.lib.units import mm
 from reportlab.pdfbase import pdfmetrics
 from reportlab.pdfbase.pdfmetrics import stringWidth
-from reportlab.pdfbase.ttfonts import TTFont
 from reportlab.pdfgen.canvas import Canvas
 from reportlab.platypus import (
    BaseDocTemplate, Flowable, Frame, KeepTogether, NextPageTemplate,
@@ -60,7 +58,8 @@ from pretix.base.services.currencies import SOURCE_NAMES
 from pretix.base.signals import register_invoice_renderers
 from pretix.base.templatetags.money import money_filter
 from pretix.helpers.reportlab import (
-    FontFallbackParagraph, ThumbnailingImageReader, reshaper,
+    FontFallbackParagraph, ThumbnailingImageReader, register_ttf_font_if_new,
+    reshaper,
 )
 from pretix.presale.style import get_fonts

@@ -235,25 +234,25 @@ class BaseReportlabInvoiceRenderer(BaseInvoiceRenderer):
        """
        Register fonts with reportlab. By default, this registers the OpenSans font family
        """
-        pdfmetrics.registerFont(TTFont('OpenSans', finders.find('fonts/OpenSans-Regular.ttf')))
-        pdfmetrics.registerFont(TTFont('OpenSansIt', finders.find('fonts/OpenSans-Italic.ttf')))
-        pdfmetrics.registerFont(TTFont('OpenSansBd', finders.find('fonts/OpenSans-Bold.ttf')))
-        pdfmetrics.registerFont(TTFont('OpenSansBI', finders.find('fonts/OpenSans-BoldItalic.ttf')))
+        register_ttf_font_if_new('OpenSans', finders.find('fonts/OpenSans-Regular.ttf'))
+        register_ttf_font_if_new('OpenSansIt', finders.find('fonts/OpenSans-Italic.ttf'))
+        register_ttf_font_if_new('OpenSansBd', finders.find('fonts/OpenSans-Bold.ttf'))
+        register_ttf_font_if_new('OpenSansBI', finders.find('fonts/OpenSans-BoldItalic.ttf'))
        pdfmetrics.registerFontFamily('OpenSans', normal='OpenSans', bold='OpenSansBd',
                                      italic='OpenSansIt', boldItalic='OpenSansBI')

        for family, styles in get_fonts(event=self.event, pdf_support_required=True).items():
-            pdfmetrics.registerFont(TTFont(family, finders.find(styles['regular']['truetype'])))
+            register_ttf_font_if_new(family, finders.find(styles['regular']['truetype']))
            if family == self.event.settings.invoice_renderer_font:
                self.font_regular = family
                if 'bold' in styles:
                    self.font_bold = family + ' B'
            if 'italic' in styles:
-                pdfmetrics.registerFont(TTFont(family + ' I', finders.find(styles['italic']['truetype'])))
+                register_ttf_font_if_new(family + ' I', finders.find(styles['italic']['truetype']))
            if 'bold' in styles:
-                pdfmetrics.registerFont(TTFont(family + ' B', finders.find(styles['bold']['truetype'])))
+                register_ttf_font_if_new(family + ' B', finders.find(styles['bold']['truetype']))
            if 'bolditalic' in styles:
-                pdfmetrics.registerFont(TTFont(family + ' B I', finders.find(styles['bolditalic']['truetype'])))
+                register_ttf_font_if_new(family + ' B I', finders.find(styles['bolditalic']['truetype']))

    def _normalize(self, text):
        # reportlab does not support unicode combination characters
@@ -1059,7 +1058,7 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):

        def fmt(val):
            try:
-                return vat_moss.exchange_rates.format(val, self.invoice.foreign_currency_display)
+                return money_filter(val, self.invoice.foreign_currency_display)
            except ValueError:
                return localize(val) + ' ' + self.invoice.foreign_currency_display

@@ -19,8 +19,11 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
+import base64
+import hashlib
 import re

+import dns.resolver
 from django import forms
 from django.core.exceptions import ValidationError
 from django.utils.translation import gettext_lazy as _, pgettext
@@ -61,7 +64,7 @@ class PeppolIdValidator:
        "0020": "[0-9]{9}",
        "0201": "[0-9a-zA-Z]{6}",
        "0204": "[0-9]{2,12}(-[0-9A-Z]{0,30})?-[0-9]{2}",
-        "0208": "0[0-9]{9}",
+        "0208": "[01][0-9]{9}",
        "0209": ".*",
        "0210": "[A-Z0-9]+",
        "0211": "IT[0-9]{11}",
@@ -70,6 +73,9 @@ class PeppolIdValidator:
        "0205": "[A-Z0-9]+",
        "0221": "T[0-9]{13}",
        "0230": ".*",
+        "0244": "[0-9]{13}",
+        "0245": "[0-9]{10}",
+        "0246": "DE[0-9]{9}(-[0-9]{5})?(\\.[0-9A-Z]{1,8})?",
        "9901": ".*",
        "9902": "[1-9][0-9]{7}",
        "9904": "DK[0-9]{8}",
@@ -117,12 +123,14 @@ class PeppolIdValidator:
        "9951": ".*",
        "9952": ".*",
        "9953": ".*",
-        "9954": ".*",
        "9956": "0[0-9]{9}",
        "9957": ".*",
        "9959": ".*",
    }

+    def __init__(self, validate_online=False):
+        self.validate_online = validate_online
+
    def __call__(self, value):
        if ":" not in value:
            raise ValidationError(_("A Peppol participant ID always starts with a prefix, followed by a colon (:)."))
@@ -136,6 +144,28 @@ class PeppolIdValidator:
            raise ValidationError(_("The Peppol participant ID does not match the validation rules for the prefix "
                                    "%(number)s. Please reach out to us if you are sure this ID is correct."),
                                  params={"number": prefix})
+
+        if self.validate_online:
+            base_hostnames = ['edelivery.tech.ec.europa.eu', 'acc.edelivery.tech.ec.europa.eu']
+            smp_id = base64.b32encode(hashlib.sha256(value.lower().encode()).digest()).decode().rstrip("=")
+            for base_hostname in base_hostnames:
+                smp_domain = f'{smp_id}.iso6523-actorid-upis.{base_hostname}'
+                resolver = dns.resolver.Resolver()
+                try:
+                    answers = resolver.resolve(smp_domain, 'NAPTR', lifetime=1.0)
+                    if answers:
+                        return value
+                except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
+                    # ID not registered, do not set found=True
+                    pass
+                except Exception:  # noqa
+                    # Error likely on our end or infrastructure is down, allow user to proceed
+                    return value
+
+            raise ValidationError(
+                _("The Peppol participant ID is not registered on the Peppol network."),
+            )
+
        return value


@@ -149,13 +179,21 @@ class PeppolTransmissionType(TransmissionType):
    def is_available(self, event, country: Country, is_business: bool):
        return is_business and super().is_available(event, country, is_business)

+    def is_exclusive(self, event, country: Country, is_business: bool) -> bool:
+        if is_business and str(country) == "BE" and event and event.settings.invoice_address_from_country == "BE":
+            # Peppol is required to be used for intra-Belgian B2B invoices
+            return True
+        return False
+
    @property
    def invoice_address_form_fields(self) -> dict:
        return {
            "transmission_peppol_participant_id": forms.CharField(
                label=_("Peppol participant ID"),
                validators=[
-                    PeppolIdValidator(),
+                    PeppolIdValidator(
+                        validate_online=True,
+                    ),
                ]
            ),
        }
@@ -21,6 +21,7 @@
 #
 from typing import Optional

+from django.utils.translation import gettext_lazy as _
 from django_countries.fields import Country

 from pretix.base.models import Invoice, InvoiceAddress
@@ -58,15 +59,6 @@ class TransmissionType:
        """
        return 100

-    @property
-    def exclusive(self) -> bool:
-        """
-        If a transmission type is exclusive, no other type can be chosen if this type is
-        available. Use e.g. if a certain transmission type is legally required in a certain
-        jurisdiction.
-        """
-        return False
-
    @property
    def enforce_transmission(self) -> bool:
        """
@@ -82,6 +74,15 @@ class TransmissionType:
            for provider, _ in providers
        )

+    def is_exclusive(self, event, country: Country, is_business: bool) -> bool:
+        """
+        If a transmission type is exclusive, no other type can be chosen if this type is
+        available. Use e.g. if a certain transmission type is legally required in a certain
+        jurisdiction. Event can be None in organizer-level contexts. Exclusiveness has no effect if
+        the type is not available.
+        """
+        return False
+
    def invoice_address_form_fields_required(self, country: Country, is_business: bool):
        return set()

@@ -106,6 +107,22 @@ class TransmissionType:
    def transmission_info_to_form_data(self, transmission_info: dict) -> dict:
        return transmission_info

+    def describe_info(self, transmission_info: dict, country: Country, is_business: bool):
+        form_data = self.transmission_info_to_form_data(transmission_info)
+        data = []
+        visible_field_keys = self.invoice_address_form_fields_visible(country, is_business)
+        for k, f in self.invoice_address_form_fields.items():
+            if k not in visible_field_keys:
+                continue
+            v = form_data.get(k)
+            if v is True:
+                v = _("Yes")
+            elif v is False:
+                v = _("No")
+            if v:
+                data.append((f.label, v))
+        return data
+
    def pdf_watermark(self) -> Optional[str]:
        """
        Return a watermark that should be rendered across the PDF file.
@@ -294,14 +294,28 @@ def metric_values():
        channel = app.broker_connection().channel()
        if hasattr(channel, 'client') and channel.client is not None:
            client = channel.client
+            priority_steps = settings.CELERY_BROKER_TRANSPORT_OPTIONS.get("priority_steps", [0])
+            sep = settings.CELERY_BROKER_TRANSPORT_OPTIONS.get("sep", ":")
+
            for q in settings.CELERY_TASK_QUEUES:
-                llen = client.llen(q.name)
-                lfirst = client.lindex(q.name, -1)
-                metrics['pretix_celery_tasks_queued_count']['{queue="%s"}' % q.name] = llen
-                if lfirst:
-                    ldata = json.loads(lfirst)
-                    dt = time.time() - ldata.get('created', 0)
-                    metrics['pretix_celery_tasks_queued_age_seconds']['{queue="%s"}' % q.name] = dt
+                queue_lengths = []
+                queue_delays = []
+                for prio in priority_steps:
+                    if prio:
+                        qname = f"{q.name}{sep}{prio}"
+                    else:
+                        qname = q.name
+                    queue_length = client.llen(qname)
+                    queue_lengths.append(queue_length)
+                    oldest_queue_item = client.lindex(qname, -1)
+                    if oldest_queue_item:
+                        ldata = json.loads(oldest_queue_item)
+                        oldest_item_age = time.time() - ldata.get('created', 0)
+                        queue_delays.append(oldest_item_age)
+
+                metrics['pretix_celery_tasks_queued_count']['{queue="%s"}' % q.name] = sum(queue_lengths)
+                if queue_delays:
+                    metrics['pretix_celery_tasks_queued_age_seconds']['{queue="%s"}' % q.name] = max(queue_delays)
                else:
                    metrics['pretix_celery_tasks_queued_age_seconds']['{queue="%s"}' % q.name] = 0

@@ -35,7 +35,7 @@ from django.utils.translation.trans_real import (
    parse_accept_lang_header,
 )

-from pretix.base.i18n import get_language_without_region
+from pretix.base.i18n import get_language_without_region, set_region
 from pretix.base.settings import global_settings_object
 from pretix.multidomain.urlreverse import (
    get_event_domain, get_organizer_domain,
@@ -92,10 +92,14 @@ class LocaleMiddleware(MiddlewareMixin):
                )
                if '-' not in language and settings_holder.settings.region:
                    language += '-' + settings_holder.settings.region
+                if settings_holder.settings.region:
+                    set_region(settings_holder.settings.region)
        else:
            gs = global_settings_object(request)
            if '-' not in language and gs.settings.region:
                language += '-' + gs.settings.region
+            if gs.settings.region:
+                set_region(gs.settings.region)

        translation.activate(language)
        request.LANGUAGE_CODE = get_language_without_region()
@@ -0,0 +1,120 @@
+# Generated by Django 4.2.26 on 2026-01-22 13:44
+import uuid
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+import pretix.base.models.mail
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("pretixbase", "0296_invoice_invoice_from_state"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="OutgoingMail",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True, primary_key=True, serialize=False
+                    ),
+                ),
+                ("guid", models.UUIDField(db_index=True, default=uuid.uuid4)),
+                ("status", models.CharField(default="queued", max_length=200)),
+                ("created", models.DateTimeField(auto_now_add=True)),
+                ("sent", models.DateTimeField(blank=True, null=True)),
+                ("inflight_since", models.DateTimeField(blank=True, null=True)),
+                ("retry_after", models.DateTimeField(blank=True, null=True)),
+                ("error", models.TextField(null=True)),
+                ("error_detail", models.TextField(null=True)),
+                ("sensitive", models.BooleanField(default=False)),
+                ("subject", models.TextField()),
+                ("body_plain", models.TextField()),
+                ("body_html", models.TextField(null=True)),
+                ("sender", models.CharField(max_length=500)),
+                ("headers", models.JSONField(default=dict)),
+                ("to", models.JSONField(default=list)),
+                ("cc", models.JSONField(default=list)),
+                ("bcc", models.JSONField(default=list)),
+                ("recipient_count", models.IntegerField()),
+                ("should_attach_tickets", models.BooleanField(default=False)),
+                ("should_attach_ical", models.BooleanField(default=False)),
+                ("should_attach_other_files", models.JSONField(default=list)),
+                ("actual_attachments", models.JSONField(default=list)),
+                (
+                    "customer",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
+                        related_name="outgoing_mails",
+                        to="pretixbase.customer",
+                    ),
+                ),
+                (
+                    "event",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
+                        related_name="outgoing_mails",
+                        to="pretixbase.event",
+                    ),
+                ),
+                (
+                    "order",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
+                        related_name="outgoing_mails",
+                        to="pretixbase.order",
+                    ),
+                ),
+                (
+                    "orderposition",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=pretix.base.models.mail.CASCADE_IF_QUEUED,
+                        related_name="outgoing_mails",
+                        to="pretixbase.orderposition",
+                    ),
+                ),
+                (
+                    "organizer",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="outgoing_mails",
+                        to="pretixbase.organizer",
+                    ),
+                ),
+                (
+                    "should_attach_cached_files",
+                    models.ManyToManyField(
+                        related_name="outgoing_mails", to="pretixbase.cachedfile"
+                    ),
+                ),
+                (
+                    "should_attach_invoices",
+                    models.ManyToManyField(
+                        related_name="outgoing_mails", to="pretixbase.invoice"
+                    ),
+                ),
+                (
+                    "user",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="outgoing_mails",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+            options={
+                "ordering": ("-created",),
+            },
+        ),
+    ]
@@ -47,6 +47,19 @@ class DataImportError(LazyLocaleException):
        super().__init__(msg)


+def rename_duplicates(values):
+    used = set()
+    had_duplicates = False
+    for i, value in enumerate(values):
+        c = 0
+        while values[i] in used:
+            c += 1
+            values[i] = f'{value}__{c}'
+            had_duplicates = True
+        used.add(values[i])
+    return had_duplicates
+
+
 def parse_csv(file, length=None, mode="strict", charset=None):
    file.seek(0)
    data = file.read(length)
@@ -70,6 +83,7 @@ def parse_csv(file, length=None, mode="strict", charset=None):
        return None

    reader = csv.DictReader(io.StringIO(data), dialect=dialect)
+    reader._had_duplicates = rename_duplicates(reader.fieldnames)
    return reader


@@ -41,6 +41,7 @@ from .items import (
    itempicture_upload_to,
 )
 from .log import LogEntry
+from .mail import OutgoingMail
 from .media import ReusableMedium
 from .memberships import Membership, MembershipType
 from .notifications import NotificationSetting
@@ -53,7 +53,6 @@ from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
 from django_otp.models import Device
 from django_scopes import scopes_disabled
-from webauthn.helpers.structs import PublicKeyCredentialDescriptor

 from pretix.base.i18n import language
 from pretix.helpers.urls import build_absolute_uri
@@ -335,27 +334,24 @@ class User(AbstractBaseUser, PermissionsMixin, LoggingMixin):
            return self.email

    def send_security_notice(self, messages, email=None):
-        from pretix.base.services.mail import SendMailException, mail
+        from pretix.base.services.mail import mail

-        try:
-            with language(self.locale):
-                msg = '- ' + '\n- '.join(str(m) for m in messages)
+        with language(self.locale):
+            msg = '- ' + '\n- '.join(str(m) for m in messages)

-            mail(
-                email or self.email,
-                _('Account information changed'),
-                'pretixcontrol/email/security_notice.txt',
-                {
-                    'user': self,
-                    'messages': msg,
-                    'url': build_absolute_uri('control:user.settings')
-                },
-                event=None,
-                user=self,
-                locale=self.locale
-            )
-        except SendMailException:
-            pass  # Already logged
+        mail(
+            email or self.email,
+            _('Account information changed'),
+            'pretixcontrol/email/security_notice.txt',
+            {
+                'user': self,
+                'messages': msg,
+                'url': build_absolute_uri('control:user.settings')
+            },
+            event=None,
+            user=self,
+            locale=self.locale
+        )

    def send_confirmation_code(self, session, reason, email=None, state=None):
        """
@@ -708,6 +704,8 @@ class U2FDevice(Device):

    @property
    def webauthndevice(self):
+        from webauthn.helpers.structs import PublicKeyCredentialDescriptor
+
        d = json.loads(self.json_data)
        return PublicKeyCredentialDescriptor(websafe_decode(d['keyHandle']))

@@ -737,6 +735,8 @@ class WebAuthnDevice(Device):

    @property
    def webauthndevice(self):
+        from webauthn.helpers.structs import PublicKeyCredentialDescriptor
+
        return PublicKeyCredentialDescriptor(websafe_decode(self.credential_id))

    @property
@@ -31,6 +31,7 @@ from django.urls import reverse
 from django.utils.crypto import get_random_string
 from django.utils.functional import cached_property

+from pretix.helpers.celery import get_task_priority
 from pretix.helpers.json import CustomJSONEncoder


@@ -58,6 +59,37 @@ class CachedFile(models.Model):
    web_download = models.BooleanField(default=True)  # allow web download, True for backwards compatibility in plugins
    session_key = models.TextField(null=True, blank=True)  # only allow download in this session

+    def session_key_for_request(self, request, salt=None):
+        from ...api.models import OAuthAccessToken, OAuthApplication
+        from .devices import Device
+        from .organizer import TeamAPIToken
+
+        if hasattr(request, "auth") and isinstance(request.auth, OAuthAccessToken):
+            k = f'app:{request.auth.application.pk}'
+        elif hasattr(request, "auth") and isinstance(request.auth, OAuthApplication):
+            k = f'app:{request.auth.pk}'
+        elif hasattr(request, "auth") and isinstance(request.auth, TeamAPIToken):
+            k = f'token:{request.auth.pk}'
+        elif hasattr(request, "auth") and isinstance(request.auth, Device):
+            k = f'device:{request.auth.pk}'
+        elif request.session.session_key:
+            k = request.session.session_key
+        else:
+            raise ValueError("No auth method found to bind to")
+
+        if salt:
+            k = f"{k}!{salt}"
+        return k
+
+    def allowed_for_session(self, request, salt=None):
+        return (
+            not self.session_key or
+            self.session_key_for_request(request, salt) == self.session_key
+        )
+
+    def bind_to_session(self, request, salt=None):
+        self.session_key = self.session_key_for_request(request, salt)
+

@receiver(post_delete, sender=CachedFile)
 def cached_file_delete(sender, instance, **kwargs):
@@ -98,6 +130,8 @@ class LoggingMixin:
            organizer_id = self.event.organizer_id
        elif hasattr(self, 'organizer_id'):
            organizer_id = self.organizer_id
+        elif hasattr(self, 'issuer_id'):
+            organizer_id = self.issuer_id

        if user and not user.is_authenticated:
            user = None
@@ -131,9 +165,15 @@ class LoggingMixin:
            logentry.save()

            if logentry.notification_type:
-                notify.apply_async(args=(logentry.pk,))
+                notify.apply_async(
+                    args=(logentry.pk,),
+                    priority=get_task_priority("notifications", logentry.organizer_id),
+                )
            if logentry.webhook_type:
-                notify_webhooks.apply_async(args=(logentry.pk,))
+                notify_webhooks.apply_async(
+                    args=(logentry.pk,),
+                    priority=get_task_priority("notifications", logentry.organizer_id),
+                )

        return logentry

@@ -40,6 +40,7 @@ from i18nfield.fields import I18nCharField
 from phonenumber_field.modelfields import PhoneNumberField

 from pretix.base.banlist import banned
+from pretix.base.i18n import language
 from pretix.base.models.base import LoggedModel
 from pretix.base.models.fields import MultiStringField
 from pretix.base.models.giftcards import GiftCardTransaction
@@ -164,6 +165,28 @@ class Customer(LoggedModel):
        self.attendee_profiles.all().delete()
        self.invoice_addresses.all().delete()

+    def send_security_notice(self, message, email=None):
+        from pretix.base.services.mail import SendMailException, mail
+        from pretix.multidomain.urlreverse import build_absolute_uri
+
+        try:
+            with language(self.locale):
+                mail(
+                    email or self.email,
+                    self.organizer.settings.mail_subject_customer_security_notice,
+                    self.organizer.settings.mail_text_customer_security_notice,
+                    {
+                        **self.get_email_context(),
+                        'message': str(message),
+                        'url': build_absolute_uri(self.organizer, 'presale:organizer.customer.index')
+                    },
+                    customer=self,
+                    organizer=self.organizer,
+                    locale=self.locale
+                )
+        except SendMailException:
+            pass  # Already logged
+
    @scopes_disabled()
    def assign_identifier(self):
        charset = list('ABCDEFGHJKLMNPQRSTUVWXYZ23456789')
@@ -293,6 +316,7 @@ class Customer(LoggedModel):
            locale=self.locale,
            customer=self,
            organizer=self.organizer,
+            sensitive=True,
        )

    def usable_gift_cards(self, used_cards=[]):
@@ -349,7 +373,7 @@ class AttendeeProfile(models.Model):
    def state_name(self):
        sd = pycountry.subdivisions.get(code='{}-{}'.format(self.country, self.state))
        if sd:
-            return sd.name
+            return _(sd.name)
        return self.state

    @property
@@ -37,7 +37,7 @@ from pretix.base.decimal import round_decimal
 from pretix.base.models.base import LoggedModel

 PositionInfo = namedtuple('PositionInfo',
-                          ['item_id', 'subevent_id', 'subevent_date_from', 'line_price_gross', 'is_addon_to',
+                          ['item_id', 'subevent_id', 'subevent_date_from', 'line_price_gross', 'addon_to',
                           'voucher_discount'])


@@ -279,6 +279,42 @@ class Discount(LoggedModel):
            for idx in condition_idx_group:
                collect_potential_discounts[idx] = [(self, inf, -1, subevent_id)]

+    def _addon_idx(self, positions, idx):
+        """
+        If we have the following cart:
+
+        - Main product
+          - 10x Addon product 5€
+        - Main product
+          - 10x Addon product 5€
+
+        And we have a discount rule that grants "every 10th product is free", people tend to expect
+
+        - Main product
+          - 9x Addon product 5€
+          - 1x Addon product free
+        - Main product
+          - 9x Addon product 5€
+          - 1x Addon product free
+
+        And get confused if they get
+
+        - Main product
+          - 8x Addon product 5€
+          - 2x Addon product free
+        - Main product
+          - 10x Addon product 5€
+
+        Even if the result is the same. Therefore, we sort positions in the cart not only by price, but also by their
+        relative index within their addon group. This is only a heuristic and there are *still* scenarios where the more
+        unexpected version happens, e.g. if prices are different. We need to accept this as long as discounts work on
+        cart level and not on addon-group level, but this simple sorting reduces the number of support issues by making
+        the weird case less likely.
+        """
+        if not positions[idx].addon_to:
+            return 0
+        return len([1 for i, p in positions.items() if i < idx and p.addon_to == positions[idx].addon_to])
+
    def _apply_min_count(self, positions, condition_idx_group, benefit_idx_group, result, collect_potential_discounts, subevent_id):
        if len(condition_idx_group) < self.condition_min_count:
            return
@@ -288,8 +324,8 @@ class Discount(LoggedModel):

        if self.benefit_only_apply_to_cheapest_n_matches:
            # sort by line_price
-            condition_idx_group = sorted(condition_idx_group, key=lambda idx: (positions[idx].line_price_gross, -idx))
-            benefit_idx_group = sorted(benefit_idx_group, key=lambda idx: (positions[idx].line_price_gross, -idx))
+            condition_idx_group = sorted(condition_idx_group, key=lambda idx: (positions[idx].line_price_gross, self._addon_idx(positions, idx), -idx))
+            benefit_idx_group = sorted(benefit_idx_group, key=lambda idx: (positions[idx].line_price_gross, self._addon_idx(positions, idx), -idx))

            # Prevent over-consuming of items, i.e. if our discount is "buy 2, get 1 free", we only
            # want to match multiples of 3
@@ -434,7 +470,7 @@ class Discount(LoggedModel):
            for idx, p in positions.items():
                subevent_to_idx[p.subevent_id].append(idx)
            for v in subevent_to_idx.values():
-                v.sort(key=lambda idx: positions[idx].line_price_gross)
+                v.sort(key=lambda idx: (positions[idx].line_price_gross, self._addon_idx(positions, idx)))
            subevent_order = sorted(list(subevent_to_idx.keys()), key=lambda s: len(subevent_to_idx[s]), reverse=True)

            # Build groups of exactly condition_min_count distinct subevents
@@ -458,7 +494,7 @@ class Discount(LoggedModel):

                # Sort the list by prices, then pick one. For "buy 2 get 1 free" we apply a "pick 1 from the start
                # and 2 from the end" scheme to optimize price distribution among groups
-                candidates = sorted(candidates, key=lambda idx: positions[idx].line_price_gross)
+                candidates = sorted(candidates, key=lambda idx: (positions[idx].line_price_gross, self._addon_idx(positions, idx)))
                if len(current_group) < (self.benefit_only_apply_to_cheapest_n_matches or 0):
                    candidate = candidates[0]
                else:
@@ -594,10 +594,11 @@ class Item(LoggedModel):
        on_delete=models.SET_NULL,
        verbose_name=_("Only show after sellout of"),
        help_text=_("If you select a product here, this product will only be shown when that product is "
-                    "sold out. If combined with the option to hide sold-out products, this allows you to "
-                    "swap out products for more expensive ones once the cheaper option is sold out. There might "
-                    "be a short period in which both products are visible while all tickets of the referenced "
-                    "product are reserved, but not yet sold.")
+                    "no longer available. This will happen either because the other product has sold out or because "
+                    "the time is outside of the sales window for the other product. If combined with the option "
+                    "to hide sold-out products, this allows you to swap out products for more expensive ones once "
+                    "the cheaper option is sold out. There might be a short period in which both products are visible "
+                    "while all tickets of the referenced product are reserved, but not yet sold.")
    )
    hidden_if_item_available_mode = models.CharField(
        choices=UNAVAIL_MODES,
@@ -35,11 +35,14 @@
 import json
 import logging

+from django.conf import settings
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
 from django.db import connections, models
 from django.utils.functional import cached_property

+from pretix.helpers.celery import get_task_priority
+

 class VisibleOnlyManager(models.Manager):
    def get_queryset(self):
@@ -138,8 +141,9 @@ class LogEntry(models.Model):

        log_entry_type, meta = log_entry_types.get(action_type=self.action_type)
        if log_entry_type:
+            sender = self.event if self.event else self.organizer
            link_info = log_entry_type.get_object_link_info(self)
-            if is_app_active(self.event, meta['plugin']):
+            if is_app_active(sender, meta['plugin']):
                return make_link(link_info, log_entry_type.object_link_wrapper)
            else:
                return make_link(link_info, log_entry_type.object_link_wrapper, is_active=False,
@@ -186,7 +190,19 @@ class LogEntry(models.Model):

        to_notify = [o.id for o in objects if o.notification_type]
        if to_notify:
-            notify.apply_async(args=(to_notify,))
+            organizer_ids = set(o.organizer_id for o in objects if o.notification_type)
+            notify.apply_async(
+                args=(to_notify,),
+                priority=settings.PRIORITY_CELERY_HIGHEST_FUNC(
+                    get_task_priority("notifications", oid) for oid in organizer_ids
+                ),
+            )
        to_wh = [o.id for o in objects if o.webhook_type]
        if to_wh:
-            notify_webhooks.apply_async(args=(to_wh,))
+            organizer_ids = set(o.organizer_id for o in objects if o.webhook_type)
+            notify_webhooks.apply_async(
+                args=(to_wh,),
+                priority=settings.PRIORITY_CELERY_HIGHEST_FUNC(
+                    get_task_priority("notifications", oid) for oid in organizer_ids
+                ),
+            )
@@ -0,0 +1,222 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020  Raphael Michel and contributors
+# Copyright (C) 2020-today pretix GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+import uuid
+
+from django.core.mail import get_connection
+from django.db import models
+from django.utils.translation import gettext_lazy as _
+from django_scopes import scope, scopes_disabled
+
+
+def CASCADE_IF_QUEUED(collector, field, sub_objs, using):
+    # If the email is still queued and the thing it is related to vanishes, the email can vanish as well
+    cascade_objs = [
+        o for o in sub_objs if o.status == OutgoingMail.STATUS_QUEUED
+    ]
+    if cascade_objs:
+        models.CASCADE(collector, field, cascade_objs, using)
+
+    # In all other cases, set to NULL to keep the email on record
+    models.SET_NULL(collector, field, [o for o in sub_objs if o not in cascade_objs], using)
+
+
+class OutgoingMail(models.Model):
+    STATUS_QUEUED = "queued"
+    STATUS_WITHHELD = "withheld"
+    STATUS_INFLIGHT = "inflight"
+    STATUS_AWAITING_RETRY = "awaiting_retry"
+    STATUS_FAILED = "failed"
+    STATUS_SENT = "sent"
+    STATUS_BOUNCED = "bounced"
+    STATUS_ABORTED = "aborted"
+    STATUS_CHOICES = (
+        (STATUS_QUEUED, _("queued")),
+        (STATUS_INFLIGHT, _("being sent")),
+        (STATUS_AWAITING_RETRY, _("awaiting retry")),
+        (STATUS_WITHHELD, _("withheld")),  # for plugin use
+        (STATUS_FAILED, _("failed")),
+        (STATUS_ABORTED, _("aborted")),
+        (STATUS_SENT, _("sent")),
+        (STATUS_BOUNCED, _("bounced")),  # for plugin use
+    )
+    STATUS_LIST_ABORTABLE = {
+        STATUS_QUEUED,
+        STATUS_WITHHELD,
+        STATUS_AWAITING_RETRY,
+    }
+    STATUS_LIST_RETRYABLE = {
+        STATUS_FAILED,
+        STATUS_WITHHELD,
+    }
+
+    # The GUID is a globally unique ID for the email added to a header of the email for later tracing
+    # in bug reports etc. We could theoretically also use this as a basis for the Message-ID header, but
+    # we currently don't since we are unsure if some intermediary SMTP servers have opinions on setting
+    # their own Message-ID headers.
+    guid = models.UUIDField(db_index=True, default=uuid.uuid4)
+
+    status = models.CharField(max_length=200, choices=STATUS_CHOICES, default=STATUS_QUEUED)
+    created = models.DateTimeField(auto_now_add=True)
+
+    # sent will be the time the email was sent or the email failed
+    sent = models.DateTimeField(null=True, blank=True)
+
+    inflight_since = models.DateTimeField(null=True, blank=True)
+    retry_after = models.DateTimeField(null=True, blank=True)
+
+    error = models.TextField(null=True, blank=True)
+    error_detail = models.TextField(null=True, blank=True)
+
+    # There is a conflict here between the different purposes of the model. As a system administrator,
+    # one wants *all* emails to be persisted as long as possible to debug issues. This means that if
+    # e.g. the event or order is deleted, we want SET_NULL behavior. However, in that case, the email
+    # would be an "orphan" forever and there's no way to remove the personal information.
+    # We try to find a middle-ground with the following behaviour:
+    # - The email is always deleted if the entire organizer or user is deleted
+    # - The email is always deleted if it has not yet been sent
+    # - The email is kept in all other cases
+    # This is only an acceptable trade-off since emails are stored for a short period only, and because
+    # orders and customers are never deleted during normal operation. If we ever make this a long-term
+    # storage / email archive, we'd need to find another way to make sure personal information is removed
+    # if personal information of orders etc is removed.
+    organizer = models.ForeignKey(
+        'pretixbase.Organizer',
+        on_delete=models.CASCADE,
+        related_name='outgoing_mails',
+        null=True, blank=True,
+    )
+    event = models.ForeignKey(
+        'pretixbase.Event',
+        on_delete=CASCADE_IF_QUEUED,
+        related_name='outgoing_mails',
+        null=True, blank=True,
+    )
+    order = models.ForeignKey(
+        'pretixbase.Order',
+        on_delete=CASCADE_IF_QUEUED,
+        related_name='outgoing_mails',
+        null=True, blank=True,
+    )
+    orderposition = models.ForeignKey(
+        'pretixbase.OrderPosition',
+        on_delete=CASCADE_IF_QUEUED,
+        related_name='outgoing_mails',
+        null=True, blank=True,
+    )
+    customer = models.ForeignKey(
+        'pretixbase.Customer',
+        on_delete=CASCADE_IF_QUEUED,
+        related_name='outgoing_mails',
+        null=True, blank=True,
+    )
+    user = models.ForeignKey(
+        'pretixbase.User',
+        on_delete=models.CASCADE,
+        related_name='outgoing_mails',
+        null=True, blank=True,
+    )
+
+    sensitive = models.BooleanField(default=False)
+    subject = models.TextField()
+    body_plain = models.TextField()
+    body_html = models.TextField(null=True)
+    sender = models.CharField(max_length=500)
+    headers = models.JSONField(default=dict)
+    to = models.JSONField(default=list)
+    cc = models.JSONField(default=list)
+    bcc = models.JSONField(default=list)
+    recipient_count = models.IntegerField()
+
+    # We don't store the actual invoices, tickets or calendar invites, so if the email is re-sent at a later time, a
+    # newer version of the files might be used. We accept that risk to save on storage and also because the new
+    # version might actually be more useful.
+    should_attach_invoices = models.ManyToManyField(
+        'pretixbase.Invoice',
+        related_name='outgoing_mails'
+    )
+    should_attach_tickets = models.BooleanField(default=False)
+    should_attach_ical = models.BooleanField(default=False)
+
+    # clean_cached_files makes sure not to delete these as long as the email is in a retryable state
+    should_attach_cached_files = models.ManyToManyField(
+        'pretixbase.CachedFile',
+        related_name='outgoing_mails',
+    )
+
+    # This is used to send files stored in settings. In most cases, these aren't short-lived and should still be there
+    # if the email is sent. Otherwise, they will be skipped. We accept that risk.
+    should_attach_other_files = models.JSONField(default=list)
+
+    # [{name, type size}] of the attachments we actually setn
+    actual_attachments = models.JSONField(default=list)
+
+    class Meta:
+        ordering = ('-created',)
+
+    def get_mail_backend(self):
+        if self.event:
+            return self.event.get_mail_backend()
+        elif self.organizer:
+            return self.organizer.get_mail_backend()
+        else:
+            return get_connection(fail_silently=False)
+
+    def scope_manager(self):
+        if self.organizer:
+            return scope(organizer=self.organizer)  # noqa
+        else:
+            return scopes_disabled()  # noqa
+
+    @property
+    def is_failed(self):
+        return self.status in (
+            OutgoingMail.STATUS_FAILED,
+            OutgoingMail.STATUS_AWAITING_RETRY,
+            OutgoingMail.STATUS_BOUNCED,
+        )
+
+    def save(self, *args, **kwargs):
+        if self.orderposition_id and not self.order_id:
+            self.order = self.orderposition.order
+        if self.order_id and not self.event_id:
+            self.event = self.order.event
+        if self.event_id and not self.organizer_id:
+            self.organizer = self.event.organizer
+        if self.customer_id and not self.organizer_id:
+            self.organizer = self.customer.organizer
+        self.recipient_count = len(self.to) + len(self.cc) + len(self.bcc)
+        super().save(*args, **kwargs)
+
+    def log_parameters(self):
+        if self.order:
+            error_log_action_type = 'pretix.event.order.email.error'
+            log_target = self.order
+        elif self.customer:
+            error_log_action_type = 'pretix.customer.email.error'
+            log_target = self.customer
+        elif self.user:
+            error_log_action_type = 'pretix.user.email.error'
+            log_target = self.user
+        else:
+            error_log_action_type = 'pretix.email.error'
+            log_target = None
+        return log_target, error_log_action_type
@@ -87,7 +87,7 @@ from pretix.base.timemachine import time_machine_now

 from ...helpers import OF_SELF
 from ...helpers.countries import CachedCountries, FastCountryField
-from ...helpers.format import format_map
+from ...helpers.format import FormattedString, format_map
 from ...helpers.names import build_name
 from ...testutils.middleware import debugflags_var
 from ._transactions import (
@@ -1167,9 +1167,7 @@ class Order(LockModel, LoggedModel):
                         only be attached for this position and child positions, the link will only point to the
                         position and the attendee email will be used if available.
        """
-        from pretix.base.services.mail import (
-            SendMailException, mail, render_mail,
-        )
+        from pretix.base.services.mail import mail, render_mail

        if not self.email and not (position and position.attendee_email):
            return
@@ -1179,35 +1177,32 @@ class Order(LockModel, LoggedModel):
            if position and position.attendee_email:
                recipient = position.attendee_email

-            try:
-                email_content = render_mail(template, context)
+            email_content = render_mail(template, context)
+            if not isinstance(subject, FormattedString):
                subject = format_map(subject, context)
-                mail(
-                    recipient, subject, template, context,
-                    self.event, self.locale, self, headers=headers, sender=sender,
-                    invoices=invoices, attach_tickets=attach_tickets,
-                    position=position, auto_email=auto_email, attach_ical=attach_ical,
-                    attach_other_files=attach_other_files, attach_cached_files=attach_cached_files,
-                )
-            except SendMailException:
-                raise
-            else:
-                self.log_action(
-                    log_entry_type,
-                    user=user,
-                    auth=auth,
-                    data={
-                        'subject': subject,
-                        'message': email_content,
-                        'position': position.positionid if position else None,
-                        'recipient': recipient,
-                        'invoices': [i.pk for i in invoices] if invoices else [],
-                        'attach_tickets': attach_tickets,
-                        'attach_ical': attach_ical,
-                        'attach_other_files': attach_other_files,
-                        'attach_cached_files': [cf.filename for cf in attach_cached_files] if attach_cached_files else [],
-                    }
-                )
+            mail(
+                recipient, subject, template, context,
+                self.event, self.locale, self, headers=headers, sender=sender,
+                invoices=invoices, attach_tickets=attach_tickets,
+                position=position, auto_email=auto_email, attach_ical=attach_ical,
+                attach_other_files=attach_other_files, attach_cached_files=attach_cached_files,
+            )
+            self.log_action(
+                log_entry_type,
+                user=user,
+                auth=auth,
+                data={
+                    'subject': subject,
+                    'message': email_content,
+                    'position': position.positionid if position else None,
+                    'recipient': recipient,
+                    'invoices': [i.pk for i in invoices] if invoices else [],
+                    'attach_tickets': attach_tickets,
+                    'attach_ical': attach_ical,
+                    'attach_other_files': attach_other_files,
+                    'attach_cached_files': [cf.filename for cf in attach_cached_files] if attach_cached_files else [],
+                }
+            )

    def resend_link(self, user=None, auth=None):
        with language(self.locale, self.event.settings.region):
@@ -1675,7 +1670,7 @@ class AbstractPosition(RoundingCorrectionMixin, models.Model):
    def state_name(self):
        sd = pycountry.subdivisions.get(code='{}-{}'.format(self.country, self.state))
        if sd:
-            return sd.name
+            return _(sd.name)
        return self.state

    @property
@@ -2024,40 +2019,30 @@ class OrderPayment(models.Model):
            transmit_invoice.apply_async(args=(self.order.event_id, invoice.pk, False))

    def _send_paid_mail_attendee(self, position, user):
-        from pretix.base.services.mail import SendMailException
-
        with language(self.order.locale, self.order.event.settings.region):
            email_template = self.order.event.settings.mail_text_order_paid_attendee
            email_subject = self.order.event.settings.mail_subject_order_paid_attendee
            email_context = get_email_context(event=self.order.event, order=self.order, position=position)
-            try:
-                position.send_mail(
-                    email_subject, email_template, email_context,
-                    'pretix.event.order.email.order_paid', user,
-                    invoices=[],
-                    attach_tickets=True,
-                    attach_ical=self.order.event.settings.mail_attach_ical
-                )
-            except SendMailException:
-                logger.exception('Order paid email could not be sent')
+            position.send_mail(
+                email_subject, email_template, email_context,
+                'pretix.event.order.email.order_paid', user,
+                invoices=[],
+                attach_tickets=True,
+                attach_ical=self.order.event.settings.mail_attach_ical
+            )

    def _send_paid_mail(self, invoice, user, mail_text):
-        from pretix.base.services.mail import SendMailException
-
        with language(self.order.locale, self.order.event.settings.region):
            email_template = self.order.event.settings.mail_text_order_paid
            email_subject = self.order.event.settings.mail_subject_order_paid
            email_context = get_email_context(event=self.order.event, order=self.order, payment_info=mail_text)
-            try:
-                self.order.send_mail(
-                    email_subject, email_template, email_context,
-                    'pretix.event.order.email.order_paid', user,
-                    invoices=[invoice] if invoice else [],
-                    attach_tickets=True,
-                    attach_ical=self.order.event.settings.mail_attach_ical
-                )
-            except SendMailException:
-                logger.exception('Order paid email could not be sent')
+            self.order.send_mail(
+                email_subject, email_template, email_context,
+                'pretix.event.order.email.order_paid', user,
+                invoices=[invoice] if invoice else [],
+                attach_tickets=True,
+                attach_ical=self.order.event.settings.mail_attach_ical
+            )

    @property
    def refunded_amount(self):
@@ -2915,45 +2900,40 @@ class OrderPosition(AbstractPosition):
        :param attach_tickets: Attach tickets of this order, if they are existing and ready to download
        :param attach_ical: Attach relevant ICS files
        """
-        from pretix.base.services.mail import (
-            SendMailException, mail, render_mail,
-        )
+        from pretix.base.services.mail import mail, render_mail

        if not self.attendee_email:
            return

        with language(self.order.locale, self.order.event.settings.region):
            recipient = self.attendee_email
-            try:
-                email_content = render_mail(template, context)
+            email_content = render_mail(template, context)
+            if not isinstance(subject, FormattedString):
                subject = format_map(subject, context)
-                mail(
-                    recipient, subject, template, context,
-                    self.event, self.order.locale, order=self.order, headers=headers, sender=sender,
-                    position=self,
-                    invoices=invoices,
-                    attach_tickets=attach_tickets,
-                    attach_ical=attach_ical,
-                    attach_other_files=attach_other_files,
-                )
-            except SendMailException:
-                raise
-            else:
-                self.order.log_action(
-                    log_entry_type,
-                    user=user,
-                    auth=auth,
-                    data={
-                        'subject': subject,
-                        'message': email_content,
-                        'recipient': recipient,
-                        'invoices': [i.pk for i in invoices] if invoices else [],
-                        'attach_tickets': attach_tickets,
-                        'attach_ical': attach_ical,
-                        'attach_other_files': attach_other_files,
-                        'attach_cached_files': [],
-                    }
-                )
+            mail(
+                recipient, subject, template, context,
+                self.event, self.order.locale, order=self.order, headers=headers, sender=sender,
+                position=self,
+                invoices=invoices,
+                attach_tickets=attach_tickets,
+                attach_ical=attach_ical,
+                attach_other_files=attach_other_files,
+            )
+            self.order.log_action(
+                log_entry_type,
+                user=user,
+                auth=auth,
+                data={
+                    'subject': subject,
+                    'message': email_content,
+                    'recipient': recipient,
+                    'invoices': [i.pk for i in invoices] if invoices else [],
+                    'attach_tickets': attach_tickets,
+                    'attach_ical': attach_ical,
+                    'attach_other_files': attach_other_files,
+                    'attach_cached_files': [],
+                }
+            )

    def resend_link(self, user=None, auth=None):

@@ -3480,7 +3460,7 @@ class InvoiceAddress(models.Model):
    def state_name(self):
        sd = pycountry.subdivisions.get(code='{}-{}'.format(self.country, self.state))
        if sd:
-            return sd.name
+            return _(sd.name)
        return self.state

    @property
@@ -3529,18 +3509,10 @@ class InvoiceAddress(models.Model):
    def describe_transmission(self):
        from pretix.base.invoicing.transmission import transmission_types
        data = []
-
        t, __ = transmission_types.get(identifier=self.transmission_type)
        data.append((_("Transmission type"), t.public_name))
-        form_data = t.transmission_info_to_form_data(self.transmission_info or {})
-        for k, f in t.invoice_address_form_fields.items():
-            v = form_data.get(k)
-            if v is True:
-                v = _("Yes")
-            elif v is False:
-                v = _("No")
-            if v:
-                data.append((f.label, v))
+        if self.transmission_info:
+            data += t.describe_info(self.transmission_info, self.country, self.is_business)
        return data


@@ -22,7 +22,6 @@
 import json
 from collections import namedtuple

-import jsonschema
 from django.contrib.staticfiles import finders
 from django.core.exceptions import ValidationError
 from django.db import models
@@ -38,6 +37,8 @@ from pretix.base.models import Event, Item, LoggedModel, Organizer, SubEvent
@deconstructible
 class SeatingPlanLayoutValidator:
    def __call__(self, value):
+        import jsonschema
+
        if not isinstance(value, dict):
            try:
                val = json.loads(value)
@@ -23,7 +23,6 @@ import json
 from decimal import Decimal
 from typing import Optional

-import jsonschema
 from django.contrib.staticfiles import finders
 from django.core.exceptions import ValidationError
 from django.core.validators import MaxValueValidator, MinValueValidator
@@ -298,6 +297,8 @@ def cc_to_vat_prefix(country_code):
@deconstructible
 class CustomRulesValidator:
    def __call__(self, value):
+        import jsonschema
+
        if not isinstance(value, dict):
            try:
                val = json.loads(value)
@@ -623,7 +623,7 @@ class Voucher(LoggedModel):
        return max(1, self.min_usages - self.redeemed)

    @classmethod
-    def annotate_budget_used_orders(cls, qs):
+    def annotate_budget_used(cls, qs):
        opq = OrderPosition.objects.filter(
            voucher_id=OuterRef('pk'),
            voucher_budget_use__isnull=False,
@@ -632,7 +632,7 @@ class Voucher(LoggedModel):
                Order.STATUS_PENDING
            ]
        ).order_by().values('voucher_id').annotate(s=Sum('voucher_budget_use')).values('s')
-        return qs.annotate(budget_used_orders=Coalesce(Subquery(opq, output_field=models.DecimalField(max_digits=13, decimal_places=2)), Decimal('0.00')))
+        return qs.annotate(budget_used=Coalesce(Subquery(opq, output_field=models.DecimalField(max_digits=13, decimal_places=2)), Decimal('0.00')))

    def budget_used(self):
        ops = OrderPosition.objects.filter(
@@ -34,7 +34,8 @@ from phonenumber_field.modelfields import PhoneNumberField
 from pretix.base.email import get_email_context
 from pretix.base.i18n import language
 from pretix.base.models import User, Voucher
-from pretix.base.services.mail import SendMailException, mail, render_mail
+from pretix.base.services.mail import mail, render_mail
+from pretix.helpers import OF_SELF

 from ...helpers.format import format_map
 from ...helpers.names import build_name
@@ -158,6 +159,7 @@ class WaitingListEntry(LoggedModel):
        if availability[1] is None or availability[1] < 1:
            raise WaitingListException(_('This product is currently not available.'))

+        event = self.event
        ev = self.subevent or self.event
        if ev.seat_category_mappings.filter(product=self.item).exists():
            # Generally, we advertise the waiting list to be based on quotas only. This makes it dangerous
@@ -185,44 +187,49 @@ class WaitingListEntry(LoggedModel):
            if not free_seats:
                raise WaitingListException(_('No seat with this product is currently available.'))

-        if self.voucher:
-            raise WaitingListException(_('A voucher has already been sent to this person.'))
        if '@' not in self.email:
            raise WaitingListException(_('This entry is anonymized and can no longer be used.'))

        with transaction.atomic():
-            e = self.email
-            if self.name:
-                e += ' / ' + self.name
+            locked_wle = WaitingListEntry.objects.select_for_update(of=OF_SELF).get(pk=self.pk)
+            locked_wle.event = event
+            if locked_wle.voucher:
+                raise WaitingListException(_('A voucher has already been sent to this person.'))
+            e = locked_wle.email
+            if locked_wle.name:
+                e += ' / ' + locked_wle.name
            v = Voucher.objects.create(
-                event=self.event,
+                event=locked_wle.event,
                max_usages=1,
-                valid_until=now() + timedelta(hours=self.event.settings.waiting_list_hours),
-                item=self.item,
-                variation=self.variation,
+                valid_until=now() + timedelta(hours=locked_wle.event.settings.waiting_list_hours),
+                item=locked_wle.item,
+                variation=locked_wle.variation,
                tag='waiting-list',
                comment=_('Automatically created from waiting list entry for {email}').format(
                    email=e
                ),
                block_quota=True,
-                subevent=self.subevent,
+                subevent=locked_wle.subevent,
            )
            v.log_action('pretix.voucher.added', {
-                'item': self.item.pk,
-                'variation': self.variation.pk if self.variation else None,
+                'item': locked_wle.item.pk,
+                'variation': locked_wle.variation.pk if locked_wle.variation else None,
                'tag': 'waiting-list',
                'block_quota': True,
                'valid_until': v.valid_until.isoformat(),
                'max_usages': 1,
-                'subevent': self.subevent.pk if self.subevent else None,
+                'subevent': locked_wle.subevent.pk if locked_wle.subevent else None,
                'source': 'waitinglist',
            }, user=user, auth=auth)
            v.log_action('pretix.voucher.added.waitinglist', {
-                'email': self.email,
-                'waitinglistentry': self.pk,
+                'email': locked_wle.email,
+                'waitinglistentry': locked_wle.pk,
            }, user=user, auth=auth)
-            self.voucher = v
-            self.save()
+            locked_wle.voucher = v
+            locked_wle.save()
+
+        self.refresh_from_db()
+        self.event = event

        with language(self.locale, self.event.settings.region):
            self.send_mail(
@@ -265,34 +272,30 @@ class WaitingListEntry(LoggedModel):
        with language(self.locale, self.event.settings.region):
            recipient = self.email

-            try:
-                email_content = render_mail(template, context)
-                subject = format_map(subject, context)
-                mail(
-                    recipient, subject, template, context,
-                    self.event,
-                    self.locale,
-                    headers=headers,
-                    sender=sender,
-                    auto_email=auto_email,
-                    attach_other_files=attach_other_files,
-                    attach_cached_files=attach_cached_files,
-                )
-            except SendMailException:
-                raise
-            else:
-                self.log_action(
-                    log_entry_type,
-                    user=user,
-                    auth=auth,
-                    data={
-                        'subject': subject,
-                        'message': email_content,
-                        'recipient': recipient,
-                        'attach_other_files': attach_other_files,
-                        'attach_cached_files': [cf.filename for cf in attach_cached_files] if attach_cached_files else [],
-                    }
-                )
+            email_content = render_mail(template, context)
+            subject = format_map(subject, context)
+            mail(
+                recipient, subject, template, context,
+                self.event,
+                self.locale,
+                headers=headers,
+                sender=sender,
+                auto_email=auto_email,
+                attach_other_files=attach_other_files,
+                attach_cached_files=attach_cached_files,
+            )
+            self.log_action(
+                log_entry_type,
+                user=user,
+                auth=auth,
+                data={
+                    'subject': subject,
+                    'message': email_content,
+                    'recipient': recipient,
+                    'attach_other_files': attach_other_files,
+                    'attach_cached_files': [cf.filename for cf in attach_cached_files] if attach_cached_files else [],
+                }
+            )

    @staticmethod
    def clean_itemvar(event, item, variation):
@@ -1231,8 +1231,8 @@ class ManualPayment(BasePaymentProvider):
    def is_allowed(self, request: HttpRequest, total: Decimal=None):
        return 'pretix.plugins.manualpayment' in self.event.plugins and super().is_allowed(request, total)

-    def order_change_allowed(self, order: Order):
-        return 'pretix.plugins.manualpayment' in self.event.plugins and super().order_change_allowed(order)
+    def order_change_allowed(self, order: Order, request=None):
+        return 'pretix.plugins.manualpayment' in self.event.plugins and super().order_change_allowed(order, request)

    @property
    def public_name(self):
@@ -1646,6 +1646,13 @@ class GiftCardPayment(BasePaymentProvider):
                    'transaction_id': trans.pk,
                }
                payment.confirm(send_mail=not is_early_special_case, generate_invoice=not is_early_special_case)
+                gc.log_action(
+                    action='pretix.giftcards.transaction.payment',
+                    data={
+                        'value': trans.value,
+                        'acceptor_id': self.event.organizer.id
+                    }
+                )
        except PaymentException as e:
            payment.fail(info={'error': str(e)})
            raise e
@@ -1670,6 +1677,14 @@ class GiftCardPayment(BasePaymentProvider):
            'transaction_id': trans.pk,
        }
        refund.done()
+        gc.log_action(
+            action='pretix.giftcards.transaction.refund',
+            data={
+                'value': refund.amount,
+                'acceptor_id': self.event.organizer.id,
+                'text': refund.comment,
+            }
+        )


@receiver(register_payment_providers, dispatch_uid="payment_free")
@@ -47,7 +47,6 @@ from collections import OrderedDict, defaultdict
 from functools import partial
 from io import BytesIO

-import jsonschema
 import pypdf
 import pypdf.generic
 import reportlab.rl_config
@@ -72,9 +71,7 @@ from reportlab.lib.colors import Color
 from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_RIGHT
 from reportlab.lib.styles import ParagraphStyle
 from reportlab.lib.units import mm
-from reportlab.pdfbase import pdfmetrics
 from reportlab.pdfbase.pdfmetrics import getAscentDescent
-from reportlab.pdfbase.ttfonts import TTFont
 from reportlab.pdfgen.canvas import Canvas
 from reportlab.platypus import Paragraph

@@ -85,7 +82,9 @@ from pretix.base.signals import layout_image_variables, layout_text_variables
 from pretix.base.templatetags.money import money_filter
 from pretix.base.templatetags.phone_format import phone_format
 from pretix.helpers.daterange import datetimerange
-from pretix.helpers.reportlab import ThumbnailingImageReader, reshaper
+from pretix.helpers.reportlab import (
+    ThumbnailingImageReader, register_ttf_font_if_new, reshaper,
+)
 from pretix.presale.style import get_fonts

 logger = logging.getLogger(__name__)
@@ -795,19 +794,19 @@ class Renderer:
    def _register_fonts(cls, event: Event = None):
        if hasattr(cls, '_fonts_registered'):
            return
-        pdfmetrics.registerFont(TTFont('Open Sans', finders.find('fonts/OpenSans-Regular.ttf')))
-        pdfmetrics.registerFont(TTFont('Open Sans I', finders.find('fonts/OpenSans-Italic.ttf')))
-        pdfmetrics.registerFont(TTFont('Open Sans B', finders.find('fonts/OpenSans-Bold.ttf')))
-        pdfmetrics.registerFont(TTFont('Open Sans B I', finders.find('fonts/OpenSans-BoldItalic.ttf')))
+        register_ttf_font_if_new('Open Sans', finders.find('fonts/OpenSans-Regular.ttf'))
+        register_ttf_font_if_new('Open Sans I', finders.find('fonts/OpenSans-Italic.ttf'))
+        register_ttf_font_if_new('Open Sans B', finders.find('fonts/OpenSans-Bold.ttf'))
+        register_ttf_font_if_new('Open Sans B I', finders.find('fonts/OpenSans-BoldItalic.ttf'))

        for family, styles in get_fonts(event, pdf_support_required=True).items():
-            pdfmetrics.registerFont(TTFont(family, finders.find(styles['regular']['truetype'])))
+            register_ttf_font_if_new(family, finders.find(styles['regular']['truetype']))
            if 'italic' in styles:
-                pdfmetrics.registerFont(TTFont(family + ' I', finders.find(styles['italic']['truetype'])))
+                register_ttf_font_if_new(family + ' I', finders.find(styles['italic']['truetype']))
            if 'bold' in styles:
-                pdfmetrics.registerFont(TTFont(family + ' B', finders.find(styles['bold']['truetype'])))
+                register_ttf_font_if_new(family + ' B', finders.find(styles['bold']['truetype']))
            if 'bolditalic' in styles:
-                pdfmetrics.registerFont(TTFont(family + ' B I', finders.find(styles['bolditalic']['truetype'])))
+                register_ttf_font_if_new(family + ' B I', finders.find(styles['bolditalic']['truetype']))

        cls._fonts_registered = True

@@ -1311,6 +1310,8 @@ def _correct_page_media_box(page: pypdf.PageObject):
@deconstructible
 class PdfLayoutValidator:
    def __call__(self, value):
+        import jsonschema
+
        if not isinstance(value, dict):
            try:
                val = json.loads(value)
@@ -65,7 +65,7 @@ def get_all_plugins(*, event=None, organizer=None) -> List[type]:
            if app.name in settings.PRETIX_PLUGINS_EXCLUDE:
                continue

-            level = getattr(app, "level", PLUGIN_LEVEL_EVENT)
+            level = getattr(meta, "level", PLUGIN_LEVEL_EVENT)
            if level == PLUGIN_LEVEL_EVENT:
                if event and hasattr(app, 'is_available'):
                    if not app.is_available(event):
@@ -36,7 +36,7 @@ from pretix.base.models import (
    SubEvent, TaxRule, User, WaitingListEntry,
 )
 from pretix.base.services.locking import LockTimeoutException
-from pretix.base.services.mail import SendMailException, mail
+from pretix.base.services.mail import mail
 from pretix.base.services.orders import (
    OrderChangeManager, OrderError, _cancel_order, _try_auto_refund,
 )
@@ -53,17 +53,14 @@ logger = logging.getLogger(__name__)
 def _send_wle_mail(wle: WaitingListEntry, subject: LazyI18nString, message: LazyI18nString, subevent: SubEvent):
    with language(wle.locale, wle.event.settings.region):
        email_context = get_email_context(event_or_subevent=subevent or wle.event, event=wle.event)
-        try:
-            mail(
-                wle.email,
-                format_map(subject, email_context),
-                message,
-                email_context,
-                wle.event,
-                locale=wle.locale
-            )
-        except SendMailException:
-            logger.exception('Waiting list canceled email could not be sent')
+        mail(
+            wle.email,
+            format_map(subject, email_context),
+            message,
+            email_context,
+            wle.event,
+            locale=wle.locale
+        )


 def _send_mail(order: Order, subject: LazyI18nString, message: LazyI18nString, subevent: SubEvent,
@@ -77,14 +74,11 @@ def _send_mail(order: Order, subject: LazyI18nString, message: LazyI18nString, s
        email_context = get_email_context(event_or_subevent=subevent or order.event, refund_amount=refund_amount,
                                          order=order, position_or_address=ia, event=order.event)
        real_subject = format_map(subject, email_context)
-        try:
-            order.send_mail(
-                real_subject, message, email_context,
-                'pretix.event.order.email.event_canceled',
-                user,
-            )
-        except SendMailException:
-            logger.exception('Order canceled email could not be sent')
+        order.send_mail(
+            real_subject, message, email_context,
+            'pretix.event.order.email.event_canceled',
+            user,
+        )

        for p in positions:
            if subevent and p.subevent_id != subevent.id:
@@ -97,15 +91,12 @@ def _send_mail(order: Order, subject: LazyI18nString, message: LazyI18nString, s
                                                  refund_amount=refund_amount,
                                                  position_or_address=p,
                                                  order=order, position=p)
-                try:
-                    order.send_mail(
-                        real_subject, message, email_context,
-                        'pretix.event.order.email.event_canceled',
-                        position=p,
-                        user=user
-                    )
-                except SendMailException:
-                    logger.exception('Order canceled email could not be sent to attendee')
+                order.send_mail(
+                    real_subject, message, email_context,
+                    'pretix.event.order.email.event_canceled',
+                    position=p,
+                    user=user
+                )


@app.task(base=ProfiledEventTask, bind=True, max_retries=5, default_retry_delay=1, throws=(OrderError,))
@@ -97,6 +97,10 @@ class CartError(Exception):
        super().__init__(msg)


+class CartPositionError(CartError):
+    pass
+
+
 error_messages = {
    'busy': gettext_lazy(
        'We were not able to process your request completely as the '
@@ -106,6 +110,9 @@ error_messages = {
    'unknown_position': gettext_lazy('Unknown cart position.'),
    'subevent_required': pgettext_lazy('subevent', 'No date was specified.'),
    'not_for_sale': gettext_lazy('You selected a product which is not available for sale.'),
+    'positions_removed': gettext_lazy(
+        'Some products can no longer be purchased and have been removed from your cart for the following reason: %s'
+    ),
    'unavailable': gettext_lazy(
        'Some of the products you selected are no longer available. '
        'Please see below for details.'
@@ -258,6 +265,138 @@ def _get_voucher_availability(event, voucher_use_diff, now_dt, exclude_position_
    return vouchers_ok, _voucher_depend_on_cart


+def _check_position_constraints(
+    event: Event, item: Item, variation: ItemVariation, voucher: Voucher, subevent: SubEvent,
+    seat: Seat, sales_channel: SalesChannel, already_in_cart: bool, cart_is_expired: bool, real_now_dt: datetime,
+    item_requires_seat: bool, is_addon: bool, is_bundled: bool,
+):
+    """
+    Checks if a cart position with the given constraints can still be sold. This checks configuration and time-based
+    constraints of item, subevent, and voucher.
+
+    It does NOT
+    - check if quota/voucher/seat are still available
+    - check prices
+    - check memberships
+    - perform any checks that go beyond the single line (like item.max_per_order)
+    """
+    time_machine_now_dt = time_machine_now(real_now_dt)
+    # Item or variation disabled
+    # Item disabled or unavailable by time
+    if not item.is_available(time_machine_now_dt) or (variation and not variation.is_available(time_machine_now_dt)):
+        raise CartPositionError(error_messages['unavailable'])
+
+    # Invalid media policy for online sale
+    if item.media_policy in (Item.MEDIA_POLICY_NEW, Item.MEDIA_POLICY_REUSE_OR_NEW):
+        mt = MEDIA_TYPES[item.media_type]
+        if not mt.medium_created_by_server:
+            raise CartPositionError(error_messages['media_usage_not_implemented'])
+    elif item.media_policy == Item.MEDIA_POLICY_REUSE:
+        raise CartPositionError(error_messages['media_usage_not_implemented'])
+
+    # Item removed from sales channel
+    if not item.all_sales_channels:
+        if sales_channel.identifier not in (s.identifier for s in item.limit_sales_channels.all()):
+            raise CartPositionError(error_messages['unavailable'])
+
+    # Variation removed from sales channel
+    if variation and not variation.all_sales_channels:
+        if sales_channel.identifier not in (s.identifier for s in variation.limit_sales_channels.all()):
+            raise CartPositionError(error_messages['unavailable'])
+
+    # Item disabled or unavailable by time in subevent
+    if subevent and item.pk in subevent.item_overrides and not subevent.item_overrides[item.pk].is_available(time_machine_now_dt):
+        raise CartPositionError(error_messages['not_for_sale'])
+
+    # Variation disabled or unavailable by time in subevent
+    if subevent and variation and variation.pk in subevent.var_overrides and \
+            not subevent.var_overrides[variation.pk].is_available(time_machine_now_dt):
+        raise CartPositionError(error_messages['not_for_sale'])
+
+    # Item requires a variation (should never happen)
+    if item.has_variations and not variation:
+        raise CartPositionError(error_messages['not_for_sale'])
+
+    # Variation belongs to wrong item (should never happen)
+    if variation and variation.item_id != item.pk:
+        raise CartPositionError(error_messages['not_for_sale'])
+
+    # Voucher does not apply to product
+    if voucher and not voucher.applies_to(item, variation):
+        raise CartPositionError(error_messages['voucher_invalid_item'])
+
+    # Voucher does not apply to seat
+    if voucher and voucher.seat and voucher.seat != seat:
+        raise CartPositionError(error_messages['voucher_invalid_seat'])
+
+    # Voucher does not apply to subevent
+    if voucher and voucher.subevent_id and voucher.subevent_id != subevent.pk:
+        raise CartPositionError(error_messages['voucher_invalid_subevent'])
+
+    # Voucher expired
+    if voucher and voucher.valid_until and voucher.valid_until < time_machine_now_dt:
+        raise CartPositionError(error_messages['voucher_expired'])
+
+    # Subevent has been disabled
+    if subevent and not subevent.active:
+        raise CartPositionError(error_messages['inactive_subevent'])
+
+    # Subevent sale not started
+    if subevent and subevent.effective_presale_start and time_machine_now_dt < subevent.effective_presale_start:
+        raise CartPositionError(error_messages['not_started'])
+
+    # Subevent sale has ended
+    if subevent and subevent.presale_has_ended:
+        raise CartPositionError(error_messages['ended'])
+
+    # Payment for subevent no longer possible
+    if subevent:
+        tlv = event.settings.get('payment_term_last', as_type=RelativeDateWrapper)
+        if tlv:
+            term_last = make_aware(datetime.combine(
+                tlv.datetime(subevent).date(),
+                time(hour=23, minute=59, second=59)
+            ), event.timezone)
+            if term_last < time_machine_now_dt:
+                raise CartPositionError(error_messages['payment_ended'])
+
+    # Seat required but no seat given
+    if item_requires_seat and not seat:
+        raise CartPositionError(error_messages['seat_invalid'])
+
+    # Seat given but no seat required
+    if seat and not item_requires_seat:
+        raise CartPositionError(error_messages['seat_forbidden'])
+
+    # Item requires to be add-on but is top-level position
+    if item.category and item.category.is_addon and not is_addon:
+        raise CartPositionError(error_messages['addon_only'])
+
+    # Item requires bundling but is top-level position
+    if item.require_bundling and not is_bundled:
+        raise CartPositionError(error_messages['bundled_only'])
+
+    # Seat for wrong product
+    if seat and seat.product != item:
+        raise CartPositionError(error_messages['seat_invalid'])
+
+    # Seat blocked
+    if seat and seat.blocked and sales_channel.identifier not in event.settings.seating_allow_blocked_seats_for_channel:
+        raise CartPositionError(error_messages['seat_invalid'])
+
+    # Item requires voucher but no voucher given
+    if item.require_voucher and voucher is None and not is_bundled:
+        raise CartPositionError(error_messages['voucher_required'])
+
+    # Item or variation is hidden without voucher but no voucher is given
+    if (
+        (item.hide_without_voucher or (variation and variation.hide_without_voucher)) and
+        (voucher is None or not voucher.show_hidden_items) and
+        not is_bundled
+    ):
+        raise CartPositionError(error_messages['voucher_required'])
+
+
 class CartManager:
    AddOperation = namedtuple('AddOperation', ('count', 'item', 'variation', 'voucher', 'quotas',
                                               'addon_to', 'subevent', 'bundled', 'seat', 'listed_price',
@@ -294,6 +433,7 @@ class CartManager:
        self._widget_data = widget_data or {}
        self._sales_channel = sales_channel
        self.num_extended_positions = 0
+        self.price_change_for_extended = False

        if reservation_time:
            self._reservation_time = reservation_time
@@ -421,14 +561,14 @@ class CartManager:
            if cartsize > limit:
                raise CartError(error_messages['max_items'] % limit)

-    def _check_item_constraints(self, op, current_ops=[]):
+    def _check_item_constraints(self, op):
        if isinstance(op, (self.AddOperation, self.ExtendOperation)):
            if not (
                (isinstance(op, self.AddOperation) and op.addon_to == 'FAKE') or
                (isinstance(op, self.ExtendOperation) and op.position.is_bundled)
            ):
                if op.item.require_voucher and op.voucher is None:
-                    if getattr(op, 'voucher_ignored', False):
+                    if getattr(op, 'voucher_ignored', False):  # todo??
                        raise CartError(error_messages['voucher_redeemed'])
                    raise CartError(error_messages['voucher_required'])

@@ -440,88 +580,39 @@ class CartManager:
                        raise CartError(error_messages['voucher_redeemed'])
                    raise CartError(error_messages['voucher_required'])

-            if not op.item.is_available() or (op.variation and not op.variation.is_available()):
-                raise CartError(error_messages['unavailable'])
-
-            if op.item.media_policy in (Item.MEDIA_POLICY_NEW, Item.MEDIA_POLICY_REUSE_OR_NEW):
-                mt = MEDIA_TYPES[op.item.media_type]
-                if not mt.medium_created_by_server:
-                    raise CartError(error_messages['media_usage_not_implemented'])
-            elif op.item.media_policy == Item.MEDIA_POLICY_REUSE:
-                raise CartError(error_messages['media_usage_not_implemented'])
-
-            if not op.item.all_sales_channels:
-                if self._sales_channel.identifier not in (s.identifier for s in op.item.limit_sales_channels.all()):
-                    raise CartError(error_messages['unavailable'])
-
-            if op.variation and not op.variation.all_sales_channels:
-                if self._sales_channel.identifier not in (s.identifier for s in op.variation.limit_sales_channels.all()):
-                    raise CartError(error_messages['unavailable'])
-
-            if op.subevent and op.item.pk in op.subevent.item_overrides and not op.subevent.item_overrides[op.item.pk].is_available():
-                raise CartError(error_messages['not_for_sale'])
-
-            if op.subevent and op.variation and op.variation.pk in op.subevent.var_overrides and \
-                    not op.subevent.var_overrides[op.variation.pk].is_available():
-                raise CartError(error_messages['not_for_sale'])
-
-            if op.item.has_variations and not op.variation:
-                raise CartError(error_messages['not_for_sale'])
-
-            if op.variation and op.variation.item_id != op.item.pk:
-                raise CartError(error_messages['not_for_sale'])
-
-            if op.voucher and not op.voucher.applies_to(op.item, op.variation):
-                raise CartError(error_messages['voucher_invalid_item'])
-
-            if op.voucher and op.voucher.seat and op.voucher.seat != op.seat:
-                raise CartError(error_messages['voucher_invalid_seat'])
-
-            if op.voucher and op.voucher.subevent_id and op.voucher.subevent_id != op.subevent.pk:
-                raise CartError(error_messages['voucher_invalid_subevent'])
-
-            if op.subevent and not op.subevent.active:
-                raise CartError(error_messages['inactive_subevent'])
-
-            if op.subevent and op.subevent.presale_start and time_machine_now(self.real_now_dt) < op.subevent.presale_start:
-                raise CartError(error_messages['not_started'])
-
-            if op.subevent and op.subevent.presale_has_ended:
-                raise CartError(error_messages['ended'])
-
-            seated = self._is_seated(op.item, op.subevent)
-            if (
-                seated and (
-                    not op.seat or (
-                        op.seat.blocked and
-                        self._sales_channel.identifier not in self.event.settings.seating_allow_blocked_seats_for_channel
-                    )
-                )
-            ):
-                raise CartError(error_messages['seat_invalid'])
-            elif op.seat and not seated:
-                raise CartError(error_messages['seat_forbidden'])
-            elif op.seat and op.seat.product != op.item:
-                raise CartError(error_messages['seat_invalid'])
-            elif op.seat and op.count > 1:
+            if op.seat and op.count > 1:
                raise CartError('Invalid request: A seat can only be bought once.')

-            if op.subevent:
-                tlv = self.event.settings.get('payment_term_last', as_type=RelativeDateWrapper)
-                if tlv:
-                    term_last = make_aware(datetime.combine(
-                        tlv.datetime(op.subevent).date(),
-                        time(hour=23, minute=59, second=59)
-                    ), self.event.timezone)
-                    if term_last < time_machine_now(self.real_now_dt):
-                        raise CartError(error_messages['payment_ended'])
+            if isinstance(op, self.AddOperation):
+                is_addon = op.addon_to
+                is_bundled = op.addon_to == "FAKE"
+            else:
+                is_addon = op.position.addon_to
+                is_bundled = op.position.is_bundled

-        if isinstance(op, self.AddOperation):
-            if op.item.category and op.item.category.is_addon and not (op.addon_to and op.addon_to != 'FAKE'):
-                raise CartError(error_messages['addon_only'])
-
-            if op.item.require_bundling and not op.addon_to == 'FAKE':
-                raise CartError(error_messages['bundled_only'])
+            try:
+                _check_position_constraints(
+                    event=self.event,
+                    item=op.item,
+                    variation=op.variation,
+                    voucher=op.voucher,
+                    subevent=op.subevent,
+                    seat=op.seat,
+                    sales_channel=self._sales_channel,
+                    already_in_cart=isinstance(op, self.ExtendOperation),
+                    cart_is_expired=isinstance(op, self.ExtendOperation),
+                    real_now_dt=self.real_now_dt,
+                    item_requires_seat=self._is_seated(op.item, op.subevent),
+                    is_addon=is_addon,
+                    is_bundled=is_bundled,
+                )
+                # Quota, seat, and voucher availability is checked for in perform_operations
+                # Price changes are checked for in extend_expired_positions
+            except CartPositionError as e:
+                if e.args[0] == error_messages['voucher_required'] and getattr(op, 'voucher_ignored', False):
+                    # This is the case where someone clicks +1 on a voucher-only item with a fully redeemed voucher:
+                    raise CartPositionError(error_messages['voucher_redeemed'])
+                raise

    def _get_price(self, item: Item, variation: Optional[ItemVariation],
                   voucher: Optional[Voucher], custom_price: Optional[Decimal],
@@ -541,7 +632,7 @@ class CartManager:
            else:
                raise e

-    def extend_expired_positions(self):
+    def _extend_expired_positions(self):
        requires_seat = Exists(
            SeatCategoryMapping.objects.filter(
                Q(product=OuterRef('item'))
@@ -604,10 +695,14 @@ class CartManager:
                quotas=quotas, subevent=cp.subevent, seat=cp.seat, listed_price=listed_price,
                price_after_voucher=price_after_voucher,
            )
-            self._check_item_constraints(op)
+            try:
+                self._check_item_constraints(op)
+            except CartPositionError as e:
+                self._operations.append(self.RemoveOperation(position=cp))
+                err = error_messages['positions_removed'] % str(e)

            if cp.voucher:
-                self._voucher_use_diff[cp.voucher] += 2
+                self._voucher_use_diff[cp.voucher] += 1

            self._operations.append(op)
        return err
@@ -797,7 +892,7 @@ class CartManager:
                    custom_price_input_is_net=False,
                    voucher_ignored=False,
                )
-                self._check_item_constraints(bop, operations)
+                self._check_item_constraints(bop)
                bundled.append(bop)

            listed_price = get_listed_price(item, variation, subevent)
@@ -836,7 +931,7 @@ class CartManager:
                custom_price_input_is_net=self.event.settings.display_net_prices,
                voucher_ignored=voucher_ignored,
            )
-            self._check_item_constraints(op, operations)
+            self._check_item_constraints(op)
            operations.append(op)

        self._quota_diff.update(quota_diff)
@@ -975,7 +1070,7 @@ class CartManager:
                    custom_price_input_is_net=self.event.settings.display_net_prices,
                    voucher_ignored=False,
                )
-                self._check_item_constraints(op, operations)
+                self._check_item_constraints(op)
                operations.append(op)

        # Check constraints on the add-on combinations
@@ -1172,7 +1267,9 @@ class CartManager:
                op.position.delete()

            elif isinstance(op, (self.AddOperation, self.ExtendOperation)):
-                # Create a CartPosition for as much items as we can
+                if isinstance(op, self.ExtendOperation) and (op.position.pk in deleted_positions or not op.position.pk):
+                    continue  # Already deleted in other operation
+                # Create a CartPosition for as many items as we can
                requested_count = quota_available_count = voucher_available_count = op.count

                if op.seat:
@@ -1343,6 +1440,8 @@ class CartManager:
                        addons.delete()
                        op.position.delete()
                    elif available_count == 1:
+                        if op.price_after_voucher != op.position.price_after_voucher:
+                            self.price_change_for_extended = True
                        op.position.expires = self._expiry
                        op.position.max_extend = self._max_expiry_extend
                        op.position.listed_price = op.listed_price
@@ -1361,6 +1460,11 @@ class CartManager:
                        deleted_positions.add(op.position.pk)
                        addons.delete()
                        op.position.delete()
+                        if op.position.is_bundled:
+                            deleted_positions |= {a.pk for a in op.position.addon_to.addons.all()}
+                            deleted_positions.add(op.position.addon_to.pk)
+                            op.position.addon_to.addons.all().delete()
+                            op.position.addon_to.delete()
                    else:
                        raise AssertionError("ExtendOperation cannot affect more than one item")
            elif isinstance(op, self.VoucherOperation):
@@ -1424,7 +1528,7 @@ class CartManager:
            self._sales_channel.identifier,
            [
                (cp.item_id, cp.subevent_id, cp.subevent.date_from if cp.subevent_id else None, cp.line_price_gross,
-                 bool(cp.addon_to), cp.is_bundled, cp.listed_price - cp.price_after_voucher)
+                 cp.addon_to, cp.is_bundled, cp.listed_price - cp.price_after_voucher)
                for cp in positions
            ]
        )
@@ -1439,15 +1543,24 @@ class CartManager:

        return diff

+    def _remove_parents_if_bundles_are_removed(self):
+        removed_positions = {op.position.pk for op in self._operations if isinstance(op, self.RemoveOperation)}
+        for op in self._operations:
+            if isinstance(op, self.RemoveOperation):
+                if op.position.is_bundled and op.position.addon_to_id not in removed_positions:
+                    self._operations.append(self.RemoveOperation(position=op.position.addon_to))
+                    removed_positions.add(op.position.addon_to_id)
+
    def commit(self):
        self._check_presale_dates()
        self._check_max_cart_size()

        err = self._delete_out_of_timeframe()
-        err = self.extend_expired_positions() or err
+        err = self._extend_expired_positions() or err
        err = err or self._check_min_per_voucher()

        self._extend_expiry_of_valid_existing_positions()
+        self._remove_parents_if_bundles_are_removed()
        err = self._perform_operations() or err
        self.recompute_final_prices_and_taxes()

@@ -1526,7 +1639,7 @@ def get_fees(event, request, _total_ignored_=None, invoice_address=None, payment
        if fee.tax_rule and not fee.tax_rule.pk:
            fee.tax_rule = None  # TODO: deprecate

-    apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+    apply_rounding(event.settings.tax_rounding, invoice_address, event.currency, [*positions, *fees])
    total = sum([c.price for c in positions]) + sum([f.value for f in fees])

    if total != 0 and payments:
@@ -1566,7 +1679,7 @@ def get_fees(event, request, _total_ignored_=None, invoice_address=None, payment
                fees.append(pf)

                # Re-apply rounding as grand total has changed
-                apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+                apply_rounding(event.settings.tax_rounding, invoice_address, event.currency, [*positions, *fees])
                total = sum([c.price for c in positions]) + sum([f.value for f in fees])

                # Re-calculate to_pay as grand total has changed
@@ -1703,7 +1816,12 @@ def extend_cart_reservation(self, event: Event, cart_id: str=None, locale='en',
            try:
                cm = CartManager(event=event, cart_id=cart_id, sales_channel=sales_channel)
                cm.commit()
-                return {"success": cm.num_extended_positions, "expiry": cm._expiry, "max_expiry_extend": cm._max_expiry_extend}
+                return {
+                    "success": cm.num_extended_positions,
+                    "expiry": cm._expiry,
+                    "max_expiry_extend": cm._max_expiry_extend,
+                    "price_changed": cm.price_change_for_extended,
+                }
            except LockTimeoutException:
                self.retry()
        except (MaxRetriesExceededError, LockTimeoutException):
@@ -23,11 +23,12 @@ from datetime import timedelta

 from django.conf import settings
 from django.core.management import call_command
+from django.db.models import Exists, OuterRef
 from django.dispatch import receiver
 from django.utils.timezone import now
 from django_scopes import scopes_disabled

-from pretix.base.models import CachedCombinedTicket, CachedTicket
+from pretix.base.models import CachedCombinedTicket, CachedTicket, OutgoingMail
 from pretix.base.models.customers import CustomerSSOGrant

 from ..models import CachedFile, CartPosition, InvoiceAddress
@@ -49,7 +50,18 @@ def clean_cart_positions(sender, **kwargs):
@receiver(signal=periodic_task)
@scopes_disabled()
 def clean_cached_files(sender, **kwargs):
-    for cf in CachedFile.objects.filter(expires__isnull=False, expires__lt=now()):
+    has_queued_email = Exists(
+        OutgoingMail.objects.filter(
+            should_attach_cached_files__pk=OuterRef("pk"),
+            status__in=(
+                OutgoingMail.STATUS_QUEUED,
+                OutgoingMail.STATUS_INFLIGHT,
+                OutgoingMail.STATUS_AWAITING_RETRY,
+                OutgoingMail.STATUS_FAILED,
+            ),
+        )
+    )
+    for cf in CachedFile.objects.filter(expires__isnull=False, expires__lt=now()).exclude(has_queued_email):
        cf.delete()


@@ -121,7 +121,7 @@ class CrossSellingService:
            self.sales_channel,
            [
                (cp.item_id, cp.subevent_id, cp.subevent.date_from if cp.subevent_id else None, cp.line_price_gross,
-                 bool(cp.addon_to), cp.is_bundled,
+                 cp.addon_to, cp.is_bundled,
                 cp.listed_price - cp.price_after_voucher)
                for cp in self.cartpositions
            ],
@@ -521,9 +521,20 @@ def invoice_pdf_task(invoice: int):


 def invoice_qualified(order: Order):
-    if order.total == Decimal('0.00') or order.require_approval or \
-            order.sales_channel.identifier not in order.event.settings.get('invoice_generate_sales_channels'):
+    if order.total == Decimal('0.00'):
        return False
+    if order.require_approval:
+        return False
+    if order.sales_channel.identifier not in order.event.settings.invoice_generate_sales_channels:
+        return False
+    if order.status in (Order.STATUS_CANCELED, Order.STATUS_EXPIRED):
+        return False
+    if order.event.settings.invoice_generate_only_business:
+        try:
+            ia = order.invoice_address
+            return ia.is_business
+        except InvoiceAddress.DoesNotExist:
+            return False
    return True


@@ -19,6 +19,8 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
+import uuid
+
 import css_inline
 from django.conf import settings
 from django.template.loader import get_template
@@ -26,12 +28,15 @@ from django.utils.timezone import override
 from django_scopes import scope, scopes_disabled

 from pretix.base.i18n import language
-from pretix.base.models import LogEntry, NotificationSetting, User
+from pretix.base.models import (
+    LogEntry, NotificationSetting, OutgoingMail, User,
+)
 from pretix.base.notifications import Notification, get_all_notification_types
 from pretix.base.services.mail import mail_send_task
 from pretix.base.services.tasks import ProfiledTask, TransactionAwareTask
 from pretix.base.signals import notification
 from pretix.celery_app import app
+from pretix.helpers.celery import get_task_priority
 from pretix.helpers.urls import build_absolute_uri


@@ -88,12 +93,18 @@ def notify(logentry_ids: list):
        for um, enabled in notify_specific.items():
            user, method = um
            if enabled:
-                send_notification.apply_async(args=(logentry.id, notification_type.action_type, user.pk, method))
+                send_notification.apply_async(
+                    args=(logentry.id, notification_type.action_type, user.pk, method),
+                    priority=get_task_priority("notifications", logentry.organizer_id),
+                )

        for um, enabled in notify_global.items():
            user, method = um
            if enabled and um not in notify_specific:
-                send_notification.apply_async(args=(logentry.id, notification_type.action_type, user.pk, method))
+                send_notification.apply_async(
+                    args=(logentry.id, notification_type.action_type, user.pk, method),
+                    priority=get_task_priority("notifications", logentry.organizer_id),
+                )

        notification.send(logentry.event, logentry_id=logentry.id, notification_type=notification_type.action_type)

@@ -146,16 +157,26 @@ def send_notification_mail(notification: Notification, user: User):
    tpl_plain = get_template('pretixbase/email/notification.txt')
    body_plain = tpl_plain.render(ctx)

-    mail_send_task.apply_async(kwargs={
-        'to': [user.email],
-        'subject': '[{}] {}: {}'.format(
+    guid = uuid.uuid4()
+    m = OutgoingMail.objects.create(
+        guid=guid,
+        user=user,
+        to=[user.email],
+        subject='[{}] {}: {}'.format(
            settings.PRETIX_INSTANCE_NAME,
            notification.event.settings.mail_prefix or notification.event.slug.upper(),
            notification.title
        ),
-        'body': body_plain,
-        'html': body_html,
-        'sender': settings.MAIL_FROM_NOTIFICATIONS,
-        'headers': {},
-        'user': user.pk
+        body_plain=body_plain,
+        body_html=body_html,
+        sender=settings.MAIL_FROM_NOTIFICATIONS,
+        headers={
+            'X-Auto-Response-Suppress': 'OOF, NRN, AutoReply, RN',
+            'Auto-Submitted': 'auto-generated',
+            'X-Mailer': 'pretix',
+            'X-PX-Correlation': str(guid),
+        },
+    )
+    mail_send_task.apply_async(kwargs={
+        'outgoing_mail': m.pk,
    })
@@ -81,7 +81,7 @@ from pretix.base.models.tax import TAXED_ZERO, TaxedPrice, TaxRule
 from pretix.base.payment import GiftCardPayment, PaymentException
 from pretix.base.reldate import RelativeDateWrapper
 from pretix.base.secrets import assign_ticket_secret
-from pretix.base.services import tickets
+from pretix.base.services import cart, tickets
 from pretix.base.services.invoices import (
    generate_cancellation, generate_invoice, invoice_qualified,
    invoice_transmission_separately, order_invoice_transmission_separately,
@@ -90,7 +90,6 @@ from pretix.base.services.invoices import (
 from pretix.base.services.locking import (
    LOCK_TRUST_WINDOW, LockTimeoutException, lock_objects,
 )
-from pretix.base.services.mail import SendMailException
 from pretix.base.services.memberships import (
    create_membership, validate_memberships_in_order,
 )
@@ -130,6 +129,9 @@ class OrderError(Exception):


 error_messages = {
+    'positions_removed': gettext_lazy(
+        'Some products can no longer be purchased and have been removed from your cart for the following reason: %s'
+    ),
    'unavailable': gettext_lazy(
        'Some of the products you selected were no longer available. '
        'Please see below for details.'
@@ -182,14 +184,6 @@ error_messages = {
        'The voucher code used for one of the items in your cart is not valid for this item. We removed this item from your cart.'
    ),
    'voucher_required': gettext_lazy('You need a valid voucher code to order one of the products.'),
-    'some_subevent_not_started': gettext_lazy(
-        'The booking period for one of the events in your cart has not yet started. The '
-        'affected positions have been removed from your cart.'
-    ),
-    'some_subevent_ended': gettext_lazy(
-        'The booking period for one of the events in your cart has ended. The affected '
-        'positions have been removed from your cart.'
-    ),
    'seat_invalid': gettext_lazy('One of the seats in your order was invalid, we removed the position from your cart.'),
    'seat_unavailable': gettext_lazy('One of the seats in your order has been taken in the meantime, we removed the position from your cart.'),
    'country_blocked': gettext_lazy('One of the selected products is not available in the selected country.'),
@@ -253,6 +247,15 @@ def reactivate_order(order: Order, force: bool=False, user: User=None, auth=None
                for gc in position.issued_gift_cards.all():
                    gc = GiftCard.objects.select_for_update(of=OF_SELF).get(pk=gc.pk)
                    gc.transactions.create(value=position.price, order=order, acceptor=order.event.organizer)
+                    gc.log_action(
+                        action='pretix.giftcards.transaction.manual',
+                        user=user,
+                        auth=auth,
+                        data={
+                            'value': position.price,
+                            'acceptor_id': order.event.organizer.id
+                        }
+                    )
                    break

                for m in position.granted_memberships.all():
@@ -443,33 +446,27 @@ def approve_order(order, user=None, send_mail: bool=True, auth=None, force=False
                email_attendee_subject = order.event.settings.mail_subject_order_approved_attendee

            email_context = get_email_context(event=order.event, order=order)
-            try:
-                order.send_mail(
-                    email_subject, email_template, email_context,
-                    'pretix.event.order.email.order_approved', user,
-                    attach_tickets=True,
-                    attach_ical=order.event.settings.mail_attach_ical and (
-                        not order.event.settings.mail_attach_ical_paid_only or
-                        order.total == Decimal('0.00') or
-                        order.valid_if_pending
-                    ),
-                    invoices=[invoice] if invoice and transmit_invoice_mail else []
-                )
-            except SendMailException:
-                logger.exception('Order approved email could not be sent')
+            order.send_mail(
+                email_subject, email_template, email_context,
+                'pretix.event.order.email.order_approved', user,
+                attach_tickets=True,
+                attach_ical=order.event.settings.mail_attach_ical and (
+                    not order.event.settings.mail_attach_ical_paid_only or
+                    order.total == Decimal('0.00') or
+                    order.valid_if_pending
+                ),
+                invoices=[invoice] if invoice and transmit_invoice_mail else []
+            )

            if email_attendees:
                for p in order.positions.all():
                    if p.addon_to_id is None and p.attendee_email and p.attendee_email != order.email:
                        email_attendee_context = get_email_context(event=order.event, order=order, position=p)
-                        try:
-                            p.send_mail(
-                                email_attendee_subject, email_attendee_template, email_attendee_context,
-                                'pretix.event.order.email.order_approved', user,
-                                attach_tickets=True,
-                            )
-                        except SendMailException:
-                            logger.exception('Order approved email could not be sent to attendee')
+                        p.send_mail(
+                            email_attendee_subject, email_attendee_template, email_attendee_context,
+                            'pretix.event.order.email.order_approved', user,
+                            attach_tickets=True,
+                        )

    return order.pk

@@ -506,13 +503,10 @@ def deny_order(order, comment='', user=None, send_mail: bool=True, auth=None):
            email_template = order.event.settings.mail_text_order_denied
            email_subject = order.event.settings.mail_subject_order_denied
            email_context = get_email_context(event=order.event, order=order, comment=comment)
-            try:
-                order.send_mail(
-                    email_subject, email_template, email_context,
-                    'pretix.event.order.email.order_denied', user
-                )
-            except SendMailException:
-                logger.exception('Order denied email could not be sent')
+            order.send_mail(
+                email_subject, email_template, email_context,
+                'pretix.event.order.email.order_denied', user
+            )

    return order.pk

@@ -563,6 +557,14 @@ def _cancel_order(order, user=None, send_mail: bool=True, api_token=None, device
                    )
                else:
                    gc.transactions.create(value=-position.price, order=order, acceptor=order.event.organizer)
+                    gc.log_action(
+                        action='pretix.giftcards.transaction.manual',
+                        user=user,
+                        data={
+                            'value': -position.price,
+                            'acceptor_id': order.event.organizer.id,
+                        }
+                    )

            for m in position.granted_memberships.all():
                m.canceled = True
@@ -665,14 +667,11 @@ def _cancel_order(order, user=None, send_mail: bool=True, api_token=None, device
                email_template = order.event.settings.mail_text_order_canceled
                email_subject = order.event.settings.mail_subject_order_canceled
                email_context = get_email_context(event=order.event, order=order, comment=comment or "")
-                try:
-                    order.send_mail(
-                        email_subject, email_template, email_context,
-                        'pretix.event.order.email.order_canceled', user,
-                        invoices=transmit_invoices_mail,
-                    )
-                except SendMailException:
-                    logger.exception('Order canceled email could not be sent')
+                order.send_mail(
+                    email_subject, email_template, email_context,
+                    'pretix.event.order.email.order_canceled', user,
+                    invoices=transmit_invoices_mail,
+                )

    for p in order.payments.filter(state__in=(OrderPayment.PAYMENT_STATE_CREATED, OrderPayment.PAYMENT_STATE_PENDING)):
        try:
@@ -744,12 +743,37 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti
            deleted_positions.add(cp.pk)
            cp.delete()

-    sorted_positions = sorted(positions, key=lambda c: (-int(c.is_bundled), c.pk))
+    sorted_positions = list(sorted(positions, key=lambda c: (-int(c.is_bundled), c.pk)))

    for cp in sorted_positions:
        cp._cached_quotas = list(cp.quotas)

+    for cp in sorted_positions:
+        try:
+            cart._check_position_constraints(
+                event=event,
+                item=cp.item,
+                variation=cp.variation,
+                voucher=cp.voucher,
+                subevent=cp.subevent,
+                seat=cp.seat,
+                sales_channel=sales_channel,
+                already_in_cart=True,
+                cart_is_expired=cp.expires < now_dt,
+                real_now_dt=now_dt,
+                item_requires_seat=cp.requires_seat,
+                is_addon=bool(cp.addon_to_id),
+                is_bundled=bool(cp.addon_to_id) and cp.is_bundled,
+            )
+            # Quota, seat, and voucher availability is checked for below
+            # Prices are checked for below
+            # Memberships are checked in _create_order
+        except cart.CartPositionError as e:
+            err = error_messages['positions_removed'] % str(e)
+            delete(cp)
+
    # Create locks
+    sorted_positions = [cp for cp in sorted_positions if cp.pk and cp.pk not in deleted_positions]  # eliminate deleted
    if any(cp.expires < now() + timedelta(seconds=LOCK_TRUST_WINDOW) for cp in sorted_positions):
        # No need to perform any locking if the cart positions still guarantee everything long enough.
        full_lock_required = any(
@@ -774,15 +798,12 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti

    # Check availability
    for i, cp in enumerate(sorted_positions):
-        if cp.pk in deleted_positions:
+        if cp.pk in deleted_positions or not cp.pk:
            continue

-        if not cp.item.is_available() or (cp.variation and not cp.variation.is_available()):
-            err = err or error_messages['unavailable']
-            delete(cp)
-            continue
        quotas = cp._cached_quotas

+        # Product per order limits
        products_seen[cp.item] += 1
        if cp.item.max_per_order and products_seen[cp.item] > cp.item.max_per_order:
            err = error_messages['max_items_per_product'] % {
@@ -792,6 +813,7 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti
            delete(cp)
            break

+        # Voucher availability
        if cp.voucher:
            v_usages[cp.voucher] += 1
            if cp.voucher not in v_avail:
@@ -806,48 +828,14 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti
                delete(cp)
                continue

-        if cp.subevent and cp.subevent.presale_start and time_machine_now_dt < cp.subevent.presale_start:
-            err = err or error_messages['some_subevent_not_started']
-            delete(cp)
-            break
-
-        if cp.subevent:
-            tlv = event.settings.get('payment_term_last', as_type=RelativeDateWrapper)
-            if tlv:
-                term_last = make_aware(datetime.combine(
-                    tlv.datetime(cp.subevent).date(),
-                    time(hour=23, minute=59, second=59)
-                ), event.timezone)
-                if term_last < time_machine_now_dt:
-                    err = err or error_messages['some_subevent_ended']
-                    delete(cp)
-                    break
-
-        if cp.subevent and cp.subevent.presale_has_ended:
-            err = err or error_messages['some_subevent_ended']
-            delete(cp)
-            break
-
-        if (cp.requires_seat and not cp.seat) or (cp.seat and not cp.requires_seat) or (cp.seat and cp.seat.product != cp.item) or cp.seat in seats_seen:
+        # Check duplicate seats in order
+        if cp.seat in seats_seen:
            err = err or error_messages['seat_invalid']
            delete(cp)
            break
+
        if cp.seat:
            seats_seen.add(cp.seat)
-
-        if cp.item.require_voucher and cp.voucher is None and not cp.is_bundled:
-            delete(cp)
-            err = err or error_messages['voucher_required']
-            break
-
-        if (cp.item.hide_without_voucher or (cp.variation and cp.variation.hide_without_voucher)) and (
-                cp.voucher is None or not cp.voucher.show_hidden_items or not cp.voucher.applies_to(cp.item, cp.variation)
-        ) and not cp.is_bundled:
-            delete(cp)
-            err = error_messages['voucher_required']
-            break
-
-        if cp.seat:
            # Unlike quotas (which we blindly trust as long as the position is not expired), we check seats every
            # time, since we absolutely can not overbook a seat.
            if not cp.seat.is_available(ignore_cart=cp, ignore_voucher_id=cp.voucher_id, sales_channel=sales_channel.identifier):
@@ -855,34 +843,13 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti
                delete(cp)
                continue

-        if cp.expires >= now_dt and not cp.voucher:
-            # Other checks are not necessary
-            continue
-
+        # Check useful quota configuration
        if len(quotas) == 0:
            err = err or error_messages['unavailable']
            delete(cp)
            continue

-        if cp.subevent and cp.item.pk in cp.subevent.item_overrides and not cp.subevent.item_overrides[cp.item.pk].is_available(time_machine_now_dt):
-            err = err or error_messages['unavailable']
-            delete(cp)
-            continue
-
-        if cp.subevent and cp.variation and cp.variation.pk in cp.subevent.var_overrides and \
-                not cp.subevent.var_overrides[cp.variation.pk].is_available(time_machine_now_dt):
-            err = err or error_messages['unavailable']
-            delete(cp)
-            continue
-
-        if cp.voucher:
-            if cp.voucher.valid_until and cp.voucher.valid_until < time_machine_now_dt:
-                err = err or error_messages['voucher_expired']
-                delete(cp)
-                continue
-
        quota_ok = True
-
        ignore_all_quotas = cp.expires >= now_dt or (
            cp.voucher and (
                cp.voucher.allow_ignore_quota or (cp.voucher.block_quota and cp.voucher.quota is None)
@@ -914,7 +881,7 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti
            })

    # Check prices
-    sorted_positions = [cp for cp in sorted_positions if cp.pk and cp.pk not in deleted_positions]
+    sorted_positions = [cp for cp in sorted_positions if cp.pk and cp.pk not in deleted_positions]  # eliminate deleted
    old_total = sum(cp.price for cp in sorted_positions)
    for i, cp in enumerate(sorted_positions):
        if cp.listed_price is None:
@@ -945,13 +912,13 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti
            delete(cp)
            continue

-    sorted_positions = [cp for cp in sorted_positions if cp.pk and cp.pk not in deleted_positions]
+    sorted_positions = [cp for cp in sorted_positions if cp.pk and cp.pk not in deleted_positions]  # eliminate deleted
    discount_results = apply_discounts(
        event,
        sales_channel.identifier,
        [
            (cp.item_id, cp.subevent_id, cp.subevent.date_from if cp.subevent_id else None, cp.line_price_gross,
-             bool(cp.addon_to), cp.is_bundled, cp.listed_price - cp.price_after_voucher)
+             cp.addon_to, cp.is_bundled, cp.listed_price - cp.price_after_voucher)
            for cp in sorted_positions
        ]
    )
@@ -1005,7 +972,7 @@ def _apply_rounding_and_fees(positions: List[CartPosition], payment_requests: Li
            fee.tax_rule = None  # TODO: deprecate

    # Apply rounding to get final total in case no payment fees will be added
-    apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+    apply_rounding(event.settings.tax_rounding, address, event.currency, [*positions, *fees])
    total = sum([c.price for c in positions]) + sum([f.value for f in fees])

    payments_assigned = Decimal("0.00")
@@ -1032,7 +999,7 @@ def _apply_rounding_and_fees(positions: List[CartPosition], payment_requests: Li
            p['fee'] = pf

            # Re-apply rounding as grand total has changed
-            apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+            apply_rounding(event.settings.tax_rounding, address, event.currency, [*positions, *fees])
            total = sum([c.price for c in positions]) + sum([f.value for f in fees])

            # Re-calculate to_pay as grand total has changed
@@ -1145,46 +1112,40 @@ def _order_placed_email(event: Event, order: Order, email_template, subject_temp
                        log_entry: str, invoice, payments: List[OrderPayment], is_free=False):
    email_context = get_email_context(event=event, order=order, payments=payments)

-    try:
-        order.send_mail(
-            subject_template, email_template, email_context,
-            log_entry,
-            invoices=[invoice] if invoice else [],
-            attach_tickets=True,
-            attach_ical=event.settings.mail_attach_ical and (
-                not event.settings.mail_attach_ical_paid_only or
-                is_free or
-                order.valid_if_pending
-            ),
-            attach_other_files=[a for a in [
-                event.settings.get('mail_attachment_new_order', as_type=str, default='')[len('file://'):]
-            ] if a],
-        )
-    except SendMailException:
-        logger.exception('Order received email could not be sent')
+    order.send_mail(
+        subject_template, email_template, email_context,
+        log_entry,
+        invoices=[invoice] if invoice else [],
+        attach_tickets=True,
+        attach_ical=event.settings.mail_attach_ical and (
+            not event.settings.mail_attach_ical_paid_only or
+            is_free or
+            order.valid_if_pending
+        ),
+        attach_other_files=[a for a in [
+            event.settings.get('mail_attachment_new_order', as_type=str, default='')[len('file://'):]
+        ] if a],
+    )


 def _order_placed_email_attendee(event: Event, order: Order, position: OrderPosition, email_template, subject_template,
                                 log_entry: str, is_free=False):
    email_context = get_email_context(event=event, order=order, position=position)

-    try:
-        position.send_mail(
-            subject_template, email_template, email_context,
-            log_entry,
-            invoices=[],
-            attach_tickets=True,
-            attach_ical=event.settings.mail_attach_ical and (
-                not event.settings.mail_attach_ical_paid_only or
-                is_free or
-                order.valid_if_pending
-            ),
-            attach_other_files=[a for a in [
-                event.settings.get('mail_attachment_new_order', as_type=str, default='')[len('file://'):]
-            ] if a],
-        )
-    except SendMailException:
-        logger.exception('Order received email could not be sent to attendee')
+    position.send_mail(
+        subject_template, email_template, email_context,
+        log_entry,
+        invoices=[],
+        attach_tickets=True,
+        attach_ical=event.settings.mail_attach_ical and (
+            not event.settings.mail_attach_ical_paid_only or
+            is_free or
+            order.valid_if_pending
+        ),
+        attach_other_files=[a for a in [
+            event.settings.get('mail_attachment_new_order', as_type=str, default='')[len('file://'):]
+        ] if a],
+    )


 def _perform_order(event: Event, payment_requests: List[dict], position_ids: List[str],
@@ -1513,13 +1474,10 @@ def send_expiry_warnings(sender, **kwargs):
                        email_template = settings.mail_text_order_pending_warning
                        email_subject = settings.mail_subject_order_pending_warning

-                    try:
-                        o.send_mail(
-                            email_subject, email_template, email_context,
-                            'pretix.event.order.email.expire_warning_sent'
-                        )
-                    except SendMailException:
-                        logger.exception('Reminder email could not be sent')
+                    o.send_mail(
+                        email_subject, email_template, email_context,
+                        'pretix.event.order.email.expire_warning_sent'
+                    )


@receiver(signal=periodic_task)
@@ -1580,14 +1538,11 @@ def send_download_reminders(sender, **kwargs):
                email_template = event.settings.mail_text_download_reminder
                email_subject = event.settings.mail_subject_download_reminder
                email_context = get_email_context(event=event, order=o)
-                try:
-                    o.send_mail(
-                        email_subject, email_template, email_context,
-                        'pretix.event.order.email.download_reminder_sent',
-                        attach_tickets=True
-                    )
-                except SendMailException:
-                    logger.exception('Reminder email could not be sent')
+                o.send_mail(
+                    email_subject, email_template, email_context,
+                    'pretix.event.order.email.download_reminder_sent',
+                    attach_tickets=True
+                )

                if event.settings.mail_send_download_reminder_attendee:
                    for p in positions:
@@ -1601,14 +1556,11 @@ def send_download_reminders(sender, **kwargs):
                            email_template = event.settings.mail_text_download_reminder_attendee
                            email_subject = event.settings.mail_subject_download_reminder_attendee
                            email_context = get_email_context(event=event, order=o, position=p)
-                            try:
-                                o.send_mail(
-                                    email_subject, email_template, email_context,
-                                    'pretix.event.order.email.download_reminder_sent',
-                                    attach_tickets=True, position=p
-                                )
-                            except SendMailException:
-                                logger.exception('Reminder email could not be sent to attendee')
+                            o.send_mail(
+                                email_subject, email_template, email_context,
+                                'pretix.event.order.email.download_reminder_sent',
+                                attach_tickets=True, position=p
+                            )


 def notify_user_changed_order(order, user=None, auth=None, invoices=[]):
@@ -1616,13 +1568,10 @@ def notify_user_changed_order(order, user=None, auth=None, invoices=[]):
        email_template = order.event.settings.mail_text_order_changed
        email_context = get_email_context(event=order.event, order=order)
        email_subject = order.event.settings.mail_subject_order_changed
-        try:
-            order.send_mail(
-                email_subject, email_template, email_context,
-                'pretix.event.order.email.order_changed', user, auth=auth, invoices=invoices, attach_tickets=True,
-            )
-        except SendMailException:
-            logger.exception('Order changed email could not be sent')
+        order.send_mail(
+            email_subject, email_template, email_context,
+            'pretix.event.order.email.order_changed', user, auth=auth, invoices=invoices, attach_tickets=True,
+        )


 class OrderChangeManager:
@@ -1667,7 +1616,7 @@ class OrderChangeManager:
    MembershipOperation = namedtuple('MembershipOperation', ('position', 'membership'))
    CancelOperation = namedtuple('CancelOperation', ('position', 'price_diff'))
    AddOperation = namedtuple('AddOperation', ('item', 'variation', 'price', 'addon_to', 'subevent', 'seat', 'membership',
-                                               'valid_from', 'valid_until', 'is_bundled'))
+                                               'valid_from', 'valid_until', 'is_bundled', 'result'))
    SplitOperation = namedtuple('SplitOperation', ('position',))
    FeeValueOperation = namedtuple('FeeValueOperation', ('fee', 'value', 'price_diff'))
    AddFeeOperation = namedtuple('AddFeeOperation', ('fee', 'price_diff'))
@@ -1678,6 +1627,19 @@ class OrderChangeManager:
    ChangeValidUntilOperation = namedtuple('ChangeValidUntilOperation', ('position', 'valid_until'))
    AddBlockOperation = namedtuple('AddBlockOperation', ('position', 'block_name', 'ignore_from_quota_while_blocked'))
    RemoveBlockOperation = namedtuple('RemoveBlockOperation', ('position', 'block_name', 'ignore_from_quota_while_blocked'))
+    ForceRecomputeOperation = namedtuple('ForceRecomputeOperation', tuple())
+
+    class AddPositionResult:
+        _position: Optional[OrderPosition]
+
+        def __init__(self):
+            self._position = None
+
+        @property
+        def position(self) -> OrderPosition:
+            if self._position is None:
+                raise RuntimeError("Order position has not been created yet. Call commit() first on OrderChangeManager.")
+            return self._position

    def __init__(self, order: Order, user=None, auth=None, notify=True, reissue_invoice=True, allow_blocked_seats=False):
        self.order = order
@@ -1829,6 +1791,7 @@ class OrderChangeManager:
        positions = self.order.positions.select_related('item', 'item__tax_rule')
        ia = self._invoice_address
        tax_rules = self._current_tax_rules()
+        self._operations.append(self.ForceRecomputeOperation())

        for pos in positions:
            tax_rule = tax_rules.get(pos.pk, pos.tax_rule)
@@ -1883,7 +1846,7 @@ class OrderChangeManager:

    def add_position(self, item: Item, variation: ItemVariation, price: Decimal, addon_to: OrderPosition = None,
                     subevent: SubEvent = None, seat: Seat = None, membership: Membership = None,
-                     valid_from: datetime = None, valid_until: datetime = None):
+                     valid_from: datetime = None, valid_until: datetime = None) -> 'OrderChangeManager.AddPositionResult':
        if isinstance(seat, str):
            if not seat:
                seat = None
@@ -1942,8 +1905,11 @@ class OrderChangeManager:
        self._quotadiff.update(new_quotas)
        if seat:
            self._seatdiff.update([seat])
+
+        result = self.AddPositionResult()
        self._operations.append(self.AddOperation(item, variation, price, addon_to, subevent, seat, membership,
-                                                  valid_from, valid_until, is_bundled))
+                                                  valid_from, valid_until, is_bundled, result))
+        return result

    def split(self, position: OrderPosition):
        if self.order.event.settings.invoice_include_free or position.price != Decimal('0.00'):
@@ -2116,6 +2082,43 @@ class OrderChangeManager:
                    )
                    item_counts[item] += 1

+        # Detect removed add-ons and create RemoveOperations
+        for cp, al in list(current_addons.items()):
+            for k, v in al.items():
+                input_num = input_addons[cp.id].get(k, 0)
+                current_num = len(current_addons[cp].get(k, []))
+                if input_num < current_num:
+                    for a in current_addons[cp][k][:current_num - input_num]:
+                        if a.canceled:
+                            continue
+                        is_unavailable = (
+                            # If an item is no longer available due to time, it should usually also be no longer
+                            # user-removable, because e.g. the stock has already been ordered.
+                            # We always pass has_voucher=True because if a product now requires a voucher, it usually does
+                            # not mean it should be unremovable for others.
+                            # This also prevents accidental removal through the UI because a hidden product will no longer
+                            # be part of the input.
+                            (a.variation and a.variation.unavailability_reason(has_voucher=True, subevent=a.subevent))
+                            or (a.variation and not a.variation.all_sales_channels and not a.variation.limit_sales_channels.contains(self.order.sales_channel))
+                            or a.item.unavailability_reason(has_voucher=True, subevent=a.subevent)
+                            or (
+                                not a.item.all_sales_channels and
+                                not a.item.limit_sales_channels.contains(self.order.sales_channel)
+                            )
+                        )
+                        if is_unavailable:
+                            # "Re-select" add-on
+                            selected_addons[cp.id, a.item.category_id][a.item_id, a.variation_id] += 1
+                            continue
+                        if a.checkins.filter(list__consider_tickets_used=True).exists():
+                            raise OrderError(
+                                error_messages['addon_already_checked_in'] % {
+                                    'addon': str(a.item.name),
+                                }
+                            )
+                        self.cancel(a)
+                        item_counts[a.item] -= 1
+
        # Check constraints on the add-on combinations
        for op in toplevel_op:
            item = op.item
@@ -2148,41 +2151,6 @@ class OrderChangeManager:
                        }
                    )

-        # Detect removed add-ons and create RemoveOperations
-        for cp, al in list(current_addons.items()):
-            for k, v in al.items():
-                input_num = input_addons[cp.id].get(k, 0)
-                current_num = len(current_addons[cp].get(k, []))
-                if input_num < current_num:
-                    for a in current_addons[cp][k][:current_num - input_num]:
-                        if a.canceled:
-                            continue
-                        is_unavailable = (
-                            # If an item is no longer available due to time, it should usually also be no longer
-                            # user-removable, because e.g. the stock has already been ordered.
-                            # We always pass has_voucher=True because if a product now requires a voucher, it usually does
-                            # not mean it should be unremovable for others.
-                            # This also prevents accidental removal through the UI because a hidden product will no longer
-                            # be part of the input.
-                            (a.variation and a.variation.unavailability_reason(has_voucher=True, subevent=a.subevent))
-                            or (a.variation and not a.variation.all_sales_channels and not a.variation.limit_sales_channels.contains(self.order.sales_channel))
-                            or a.item.unavailability_reason(has_voucher=True, subevent=a.subevent)
-                            or (
-                                not item.all_sales_channels and
-                                not item.limit_sales_channels.contains(self.order.sales_channel)
-                            )
-                        )
-                        if is_unavailable:
-                            continue
-                        if a.checkins.filter(list__consider_tickets_used=True).exists():
-                            raise OrderError(
-                                error_messages['addon_already_checked_in'] % {
-                                    'addon': str(a.item.name),
-                                }
-                            )
-                        self.cancel(a)
-                        item_counts[a.item] -= 1
-
        for item, count in item_counts.items():
            if count == 0:
                continue
@@ -2483,6 +2451,15 @@ class OrderChangeManager:
                        ))
                    else:
                        gc.transactions.create(value=-position.price, order=self.order, acceptor=self.order.event.organizer)
+                        gc.log_action(
+                            action='pretix.giftcards.transaction.manual',
+                            user=self.user,
+                            auth=self.auth,
+                            data={
+                                'value': -position.price,
+                                'acceptor_id': self.order.event.organizer.id
+                            }
+                        )

                for m in position.granted_memberships.with_usages().all():
                    m.canceled = True
@@ -2500,6 +2477,15 @@ class OrderChangeManager:
                            ))
                        else:
                            gc.transactions.create(value=-opa.position.price, order=self.order, acceptor=self.order.event.organizer)
+                            gc.log_action(
+                                action='pretix.giftcards.transaction.manual',
+                                user=self.user,
+                                auth=self.auth,
+                                data={
+                                    'value': -opa.position.price,
+                                    'acceptor_id': self.order.event.organizer.id
+                                }
+                            )

                    for m in opa.granted_memberships.with_usages().all():
                        m.canceled = True
@@ -2562,6 +2548,7 @@ class OrderChangeManager:
                    'valid_from': op.valid_from.isoformat() if op.valid_from else None,
                    'valid_until': op.valid_until.isoformat() if op.valid_until else None,
                })
+                op.result._position = pos
            elif isinstance(op, self.SplitOperation):
                position = position_cache.setdefault(op.position.pk, op.position)
                split_positions.append(position)
@@ -2661,6 +2648,10 @@ class OrderChangeManager:
                        except BlockedTicketSecret.DoesNotExist:
                            pass
                # todo: revoke list handling
+            elif isinstance(op, self.ForceRecomputeOperation):
+                self.order.log_action('pretix.event.order.changed.recomputed', user=self.user, auth=self.auth, data={})
+            else:
+                raise TypeError(f"Unknown operation {type(op)}")

        for p in secret_dirty:
            assign_ticket_secret(
@@ -2715,7 +2706,10 @@ class OrderChangeManager:
            fees.append(new_fee)

        changed_by_rounding = set(apply_rounding(
-            self.order.tax_rounding_mode, self.event.currency, [p for p in split_positions if not p.canceled] + fees
+            self.order.tax_rounding_mode,
+            self._invoice_address,
+            self.event.currency,
+            [p for p in split_positions if not p.canceled] + fees
        ))
        split_order.total = sum([p.price for p in split_positions if not p.canceled])

@@ -2737,7 +2731,10 @@ class OrderChangeManager:
                fee.delete()

            changed_by_rounding |= set(apply_rounding(
-                self.order.tax_rounding_mode, self.event.currency, [p for p in split_positions if not p.canceled] + fees
+                self.order.tax_rounding_mode,
+                self._invoice_address,
+                self.event.currency,
+                [p for p in split_positions if not p.canceled] + fees
            ))
            split_order.total = sum([p.price for p in split_positions if not p.canceled]) + sum([f.value for f in fees])

@@ -2854,7 +2851,12 @@ class OrderChangeManager:
        if fee_changed:
            fees = list(self.order.fees.all())

-        changed = apply_rounding(self.order.tax_rounding_mode, self.order.event.currency, [*positions, *fees])
+        changed = apply_rounding(
+            self.order.tax_rounding_mode,
+            self._invoice_address,
+            self.order.event.currency,
+            [*positions, *fees]
+        )
        for l in changed:
            if isinstance(l, OrderPosition):
                l.save(update_fields=[
@@ -3152,7 +3154,10 @@ def _try_auto_refund(order, auto_refund=True, manual_refund=False, allow_partial
                customer=order.customer,
                testmode=order.testmode
            )
-            giftcard.log_action('pretix.giftcards.created', data={})
+            giftcard.log_action(
+                action='pretix.giftcards.created',
+                data={}
+            )
            r = order.refunds.create(
                order=order,
                payment=None,
@@ -3290,8 +3295,12 @@ def change_payment_provider(order: Order, payment_provider, amount=None, new_pay

    positions = list(order.positions.all())
    fees = list(order.fees.all())
+    try:
+        ia = order.invoice_address
+    except InvoiceAddress.DoesNotExist:
+        ia = None
    rounding_changed = set(apply_rounding(
-        order.tax_rounding_mode, order.event.currency, [*positions, *[f for f in fees if f.pk != fee.pk]]
+        order.tax_rounding_mode, ia, order.event.currency, [*positions, *[f for f in fees if f.pk != fee.pk]]
    ))
    total_without_fee = sum(c.price for c in positions) + sum(f.value for f in fees if f.pk != fee.pk)
    pending_sum_without_fee = max(Decimal("0.00"), total_without_fee - already_paid)
@@ -3316,7 +3325,7 @@ def change_payment_provider(order: Order, payment_provider, amount=None, new_pay
        fee = None

    rounding_changed |= set(apply_rounding(
-        order.tax_rounding_mode, order.event.currency, [*positions, *fees]
+        order.tax_rounding_mode, ia, order.event.currency, [*positions, *fees]
    ))
    for l in rounding_changed:
        if isinstance(l, OrderPosition):
@@ -3435,7 +3444,17 @@ def signal_listener_issue_giftcards(sender: Event, order: Order, **kwargs):
                    currency=sender.currency, issued_in=p, testmode=order.testmode,
                    expires=sender.organizer.default_gift_card_expiry,
                )
-                gc.transactions.create(value=p.price - issued, order=order, acceptor=sender.organizer)
+                gc.log_action(
+                    action='pretix.giftcards.created',
+                )
+                trans = gc.transactions.create(value=p.price - issued, order=order, acceptor=sender.organizer)
+                gc.log_action(
+                    action='pretix.giftcards.transaction.manual',
+                    data={
+                        'value': trans.value,
+                        'acceptor_id': order.event.organizer.id,
+                    }
+                )
                any_giftcards = True
                p.secret = gc.secret
                p.save(update_fields=['secret'])
@@ -801,7 +801,11 @@ def get_sample_context(event, context_parameters, rich=True):
        sample = v.render_sample(event)
        if isinstance(sample, PlainHtmlAlternativeString):
            context_dict[k] = PlainHtmlAlternativeString(
-                sample.plain,
+                '<{el} class="placeholder" title="{title}">{plain}</{el}>'.format(
+                    el='span',
+                    title=lbl,
+                    plain=escape(sample.plain),
+                ),
                '<{el} class="placeholder placeholder-html" title="{title}">{html}</{el}>'.format(
                    el='div' if sample.is_block else 'span',
                    title=lbl,
@@ -174,7 +174,9 @@ def apply_discounts(event: Event, sales_channel: Union[str, SalesChannel],

    :param event: Event the cart belongs to
    :param sales_channel: Sales channel the cart was created with
-    :param positions: Tuple of the form ``(item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, is_bundled, voucher_discount)``
+    :param positions: Tuple of the form ``(item_id, subevent_id, subevent_date_from, line_price_gross, addon_to_id, is_bundled, voucher_discount)``
+                      ``addon_to_id`` does not have to be the proper ID, any identifier is okay, even ``True``/``False`` are accepted, but
+                      a better result may be given if addons to the same main product have the same distinct value.
    :param collect_potential_discounts: If a `defaultdict(list)` is supplied, all discounts that could be applied to the cart
    based on the "consumed" items, but lack matching "benefitting" items will be collected therein.
    The dict will contain a mapping from index in the `positions` list of the item that could be consumed, to a list
@@ -196,9 +198,9 @@ def apply_discounts(event: Event, sales_channel: Union[str, SalesChannel],
    ).prefetch_related('condition_limit_products', 'benefit_limit_products').order_by('position', 'pk')
    for discount in discount_qs:
        result = discount.apply({
-            idx: PositionInfo(item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, voucher_discount)
+            idx: PositionInfo(item_id, subevent_id, subevent_date_from, line_price_gross, addon_to, voucher_discount)
            for
-            idx, (item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, is_bundled, voucher_discount)
+            idx, (item_id, subevent_id, subevent_date_from, line_price_gross, addon_to, is_bundled, voucher_discount)
            in enumerate(positions)
            if not is_bundled and idx not in new_prices
        }, collect_potential_discounts)
@@ -209,7 +211,8 @@ def apply_discounts(event: Event, sales_channel: Union[str, SalesChannel],
    return [new_prices.get(idx, (p[3], None)) for idx, p in enumerate(positions)]


-def apply_rounding(rounding_mode: Literal["line", "sum_by_net", "sum_by_net_keep_gross"], currency: str,
+def apply_rounding(rounding_mode: Literal["line", "sum_by_net", "sum_by_net_only_business", "sum_by_net_keep_gross"],
+                   invoice_address: Optional[InvoiceAddress], currency: str,
                   lines: List[Union[OrderPosition, CartPosition, OrderFee]]) -> list:
    """
    Given a list of order positions / cart positions / order fees (may be mixed), applies the given rounding mode
@@ -224,11 +227,17 @@ def apply_rounding(rounding_mode: Literal["line", "sum_by_net", "sum_by_net_keep
    When rounding mode is set to ``"sum_by_net"``, the gross prices and tax values of the individual lines will be
    adjusted such that the per-taxrate/taxcode subtotal is rounded correctly. The net prices will stay constant.

-    :param rounding_mode: One of ``"line"``, ``"sum_by_net"``, or ``"sum_by_net_keep_gross"``.
+    :param rounding_mode: One of ``"line"``, ``"sum_by_net"``, ``"sum_by_net_only_business"``, or ``"sum_by_net_keep_gross"``.
+    :param invoice_address: The invoice address, or ``None``
    :param currency: Currency that will be used to determine rounding precision
    :param lines: List of order/cart contents
    :return: Collection of ``lines`` members that have been changed and may need to be persisted to the database.
    """
+    if rounding_mode == "sum_by_net_only_business":
+        if invoice_address and invoice_address.is_business:
+            rounding_mode = "sum_by_net"
+        else:
+            rounding_mode = "line"

    def _key(line):
        return (line.tax_rate, line.tax_code or "")
@@ -48,7 +48,7 @@ from django.utils.translation import gettext_lazy as _

 from pretix.base.i18n import language
 from pretix.base.models import CachedFile, Event, User, cachedfile_name
-from pretix.base.services.mail import SendMailException, mail
+from pretix.base.services.mail import mail
 from pretix.base.services.tasks import ProfiledEventTask
 from pretix.base.shredder import ShredError
 from pretix.celery_app import app
@@ -171,21 +171,18 @@ def shred(self, event: Event, fileid: str, confirm_code: str, user: int=None, lo

    if user:
        with language(user.locale):
-            try:
-                mail(
-                    user.email,
-                    _('Data shredding completed'),
-                    'pretixbase/email/shred_completed.txt',
-                    {
-                        'user': user,
-                        'organizer': event.organizer.name,
-                        'event': str(event.name),
-                        'start_time': date_format(parse(indexdata['time']).astimezone(event.timezone), 'SHORT_DATETIME_FORMAT'),
-                        'shredders': ', '.join([str(s.verbose_name) for s in shredders])
-                    },
-                    event=None,
-                    user=user,
-                    locale=user.locale,
-                )
-            except SendMailException:
-                pass  # Already logged
+            mail(
+                user.email,
+                _('Data shredding completed'),
+                'pretixbase/email/shred_completed.txt',
+                {
+                    'user': user,
+                    'organizer': event.organizer.name,
+                    'event': str(event.name),
+                    'start_time': date_format(parse(indexdata['time']).astimezone(event.timezone), 'SHORT_DATETIME_FORMAT'),
+                    'shredders': ', '.join([str(s.verbose_name) for s in shredders])
+                },
+                event=None,
+                user=user,
+                locale=user.locale,
+            )
@@ -112,7 +112,8 @@ def dictsum(*dicts) -> dict:

 def order_overview(
        event: Event, subevent: SubEvent=None, date_filter='', date_from=None, date_until=None, fees=False,
-        admission_only=False, base_qs=None, base_fees_qs=None, subevent_date_from=None, subevent_date_until=None
+        admission_only=False, base_qs=None, base_fees_qs=None, subevent_date_from=None, subevent_date_until=None,
+        skip_empty_lines=False,
 ) -> Tuple[List[Tuple[ItemCategory, List[Item]]], Dict[str, Tuple[Decimal, Decimal]]]:
    items = event.items.all().select_related(
        'category',  # for re-grouping
@@ -205,13 +206,21 @@ def order_overview(
                for l in states.keys():
                    var.num[l] = num[l].get((item.id, variid), (0, 0, 0))
                var.num['total'] = num['total'].get((item.id, variid), (0, 0, 0))
+                var._skip = all(v[0] == 0 for v in var.num.values())
            for l in states.keys():
                item.num[l] = tuplesum(var.num[l] for var in item.all_variations)
            item.num['total'] = tuplesum(var.num['total'] for var in item.all_variations)
+            if skip_empty_lines:
+                item.all_variations = [v for v in item.all_variations if not v._skip]
+                item._skip = not item.all_variations
        else:
            for l in states.keys():
                item.num[l] = num[l].get((item.id, None), (0, 0, 0))
            item.num['total'] = num['total'].get((item.id, None), (0, 0, 0))
+            item._skip = all(v[0] == 0 for v in item.num.values())
+
+    if skip_empty_lines:
+        items = [i for i in items if not i._skip]

    nonecat = ItemCategory(name=_('Uncategorized'))
    # Regroup those by category
@@ -27,7 +27,6 @@ from decimal import Decimal
 from xml.etree import ElementTree

 import requests
-import vat_moss.id
 from django.conf import settings
 from django.utils.translation import gettext_lazy as _
 from zeep import Client, Transport
@@ -42,14 +41,142 @@ logger = logging.getLogger(__name__)
 error_messages = {
    'unavailable': _(
        'Your VAT ID could not be checked, as the VAT checking service of '
-        'your country is currently not available. We will therefore '
-        'need to charge VAT on your invoice. You can get the tax amount '
-        'back via the VAT reimbursement process.'
+        'your country is currently not available. We will therefore need to '
+        'charge you the same tax rate as if you did not enter a VAT ID.'
    ),
    'invalid': _('This VAT ID is not valid. Please re-check your input.'),
    'country_mismatch': _('Your VAT ID does not match the selected country.'),
 }

+VAT_ID_PATTERNS = {
+    # Patterns generated by consulting the following URLs:
+    #
+    #  - http://en.wikipedia.org/wiki/VAT_identification_number
+    #  - http://ec.europa.eu/taxation_customs/vies/faq.html
+    #  - https://euipo.europa.eu/tunnel-web/secure/webdav/guest/document_library/Documents/COSME/VAT%20numbers%20EU.pdf
+    #  - http://www.skatteetaten.no/en/International-pages/Felles-innhold-benyttes-i-flere-malgrupper/Brochure/Guide-to-value-added-tax-in-Norway/?chapter=7159
+    'AT': {  # Austria
+        'regex': '^U\\d{8}$',
+        'country_code': 'AT'
+    },
+    'BE': {  # Belgium
+        'regex': '^(1|0?)\\d{9}$',
+        'country_code': 'BE'
+    },
+    'BG': {  # Bulgaria
+        'regex': '^\\d{9,10}$',
+        'country_code': 'BG'
+    },
+    'CH': {  # Switzerland
+        'regex': '^\\dE{9}$',
+        'country_code': 'CH'
+    },
+    'CY': {  # Cyprus
+        'regex': '^\\d{8}[A-Z]$',
+        'country_code': 'CY'
+    },
+    'CZ': {  # Czech Republic
+        'regex': '^\\d{8,10}$',
+        'country_code': 'CZ'
+    },
+    'DE': {  # Germany
+        'regex': '^\\d{9}$',
+        'country_code': 'DE'
+    },
+    'DK': {  # Denmark
+        'regex': '^\\d{8}$',
+        'country_code': 'DK'
+    },
+    'EE': {  # Estonia
+        'regex': '^\\d{9}$',
+        'country_code': 'EE'
+    },
+    'EL': {  # Greece
+        'regex': '^\\d{9}$',
+        'country_code': 'GR'
+    },
+    'ES': {  # Spain
+        'regex': '^[A-Z0-9]\\d{7}[A-Z0-9]$',
+        'country_code': 'ES'
+    },
+    'FI': {  # Finland
+        'regex': '^\\d{8}$',
+        'country_code': 'FI'
+    },
+    'FR': {  # France
+        'regex': '^[A-Z0-9]{2}\\d{9}$',
+        'country_code': 'FR'
+    },
+    'GB': {  # United Kingdom
+        'regex': '^(GD\\d{3}|HA\\d{3}|\\d{9}|\\d{12})$',
+        'country_code': 'GB'
+    },
+    'HR': {  # Croatia
+        'regex': '^\\d{11}$',
+        'country_code': 'HR'
+    },
+    'HU': {  # Hungary
+        'regex': '^\\d{8}$',
+        'country_code': 'HU'
+    },
+    'IE': {  # Ireland
+        'regex': '^(\\d{7}[A-Z]{1,2}|\\d[A-Z+*]\\d{5}[A-Z])$',
+        'country_code': 'IE'
+    },
+    'IT': {  # Italy
+        'regex': '^\\d{11}$',
+        'country_code': 'IT'
+    },
+    'LT': {  # Lithuania
+        'regex': '^(\\d{9}|\\d{12})$',
+        'country_code': 'LT'
+    },
+    'LU': {  # Luxembourg
+        'regex': '^\\d{8}$',
+        'country_code': 'LU'
+    },
+    'LV': {  # Latvia
+        'regex': '^\\d{11}$',
+        'country_code': 'LV'
+    },
+    'MT': {  # Malta
+        'regex': '^\\d{8}$',
+        'country_code': 'MT'
+    },
+    'NL': {  # Netherlands
+        'regex': '^\\d{9}B\\d{2}$',
+        'country_code': 'NL'
+    },
+    'NO': {  # Norway
+        'regex': '^\\d{9}MVA$',
+        'country_code': 'NO'
+    },
+    'PL': {  # Poland
+        'regex': '^\\d{10}$',
+        'country_code': 'PL'
+    },
+    'PT': {  # Portugal
+        'regex': '^\\d{9}$',
+        'country_code': 'PT'
+    },
+    'RO': {  # Romania
+        'regex': '^\\d{2,10}$',
+        'country_code': 'RO'
+    },
+    'SE': {  # Sweden
+        'regex': '^\\d{12}$',
+        'country_code': 'SE'
+    },
+    'SI': {  # Slovenia
+        'regex': '^\\d{8}$',
+        'country_code': 'SI'
+    },
+    'SK': {  # Slovakia
+        'regex': '^\\d{10}$',
+        'country_code': 'SK'
+    },
+}
+

 class VATIDError(Exception):
    def __init__(self, message):
@@ -64,13 +191,57 @@ class VATIDTemporaryError(VATIDError):
    pass


+def normalize_vat_id(vat_id, country_code):
+    """
+    Accepts a VAT ID and normaizes it, getting rid of spaces, periods, dashes
+    etc and converting it to upper case.
+
+    Original function from https://github.com/wbond/vat_moss-python
+    Copyright (c) 2015 Will Bond <will@wbond.net>
+    MIT License
+    """
+    if not vat_id:
+        return None
+
+    if not isinstance(vat_id, str):
+        raise TypeError('VAT ID is not a string')
+
+    if len(vat_id) < 3:
+        raise ValueError('VAT ID must be at least three character long')
+
+    # Normalize the ID for simpler regexes
+    vat_id = re.sub('\\s+', '', vat_id)
+    vat_id = vat_id.replace('-', '')
+    vat_id = vat_id.replace('.', '')
+    vat_id = vat_id.upper()
+
+    # Clean the different shapes a number can take in Switzerland depending on purpse
+    if country_code == "CH":
+        vat_id = re.sub('[^A-Z0-9]', '', vat_id.replace('HR', '').replace('MWST', ''))
+
+    # Fix people using GR prefix for Greece
+    if vat_id[0:2] == "GR" and country_code == "GR":
+        vat_id = "EL" + vat_id[2:]
+
+    # Check if we already have a valid country prefix. If not, we try to figure out if we can
+    # add one, since in some countries (e.g. Italy) it's very custom to enter it without the prefix
+    if vat_id[:2] in VAT_ID_PATTERNS and re.match(VAT_ID_PATTERNS[vat_id[0:2]]['regex'], vat_id[2:]):
+        # Prefix set and prefix matches pattern, nothing to do
+        pass
+    elif re.match(VAT_ID_PATTERNS[cc_to_vat_prefix(country_code)]['regex'], vat_id):
+        # Prefix not set but adding it fixes pattern
+        vat_id = cc_to_vat_prefix(country_code) + vat_id
+    else:
+        # We have no idea what this is
+        pass
+
+    return vat_id
+
+
 def _validate_vat_id_NO(vat_id, country_code):
    # Inspired by vat_moss library
-    if not vat_id.startswith("NO"):
-        # prefix is not usually used in Norway, but expected by vat_moss library
-        vat_id = "NO" + vat_id
    try:
-        vat_id = vat_moss.id.normalize(vat_id)
+        vat_id = normalize_vat_id(vat_id, country_code)
    except ValueError:
        raise VATIDFinalError(error_messages['invalid'])

@@ -104,7 +275,7 @@ def _validate_vat_id_NO(vat_id, country_code):
 def _validate_vat_id_EU(vat_id, country_code):
    # Inspired by vat_moss library
    try:
-        vat_id = vat_moss.id.normalize(vat_id)
+        vat_id = normalize_vat_id(vat_id, country_code)
    except ValueError:
        raise VATIDFinalError(error_messages['invalid'])

@@ -112,11 +283,10 @@ def _validate_vat_id_EU(vat_id, country_code):
        raise VATIDFinalError(error_messages['invalid'])

    number = vat_id[2:]
-
    if vat_id[:2] != cc_to_vat_prefix(country_code):
        raise VATIDFinalError(error_messages['country_mismatch'])

-    if not re.match(vat_moss.id.ID_PATTERNS[cc_to_vat_prefix(country_code)]['regex'], number):
+    if not re.match(VAT_ID_PATTERNS[cc_to_vat_prefix(country_code)]['regex'], number):
        raise VATIDFinalError(error_messages['invalid'])

    # We are relying on the country code of the normalized VAT-ID and not the user/InvoiceAddress-provided
@@ -175,9 +345,12 @@ def _validate_vat_id_EU(vat_id, country_code):

 def _validate_vat_id_CH(vat_id, country_code):
    if vat_id[:3] != 'CHE':
-        raise VATIDFinalError(_('Your VAT ID does not match the selected country.'))
+        raise VATIDFinalError(error_messages['country_mismatch'])

-    vat_id = re.sub('[^A-Z0-9]', '', vat_id.replace('HR', '').replace('MWST', ''))
+    try:
+        vat_id = normalize_vat_id(vat_id, country_code)
+    except ValueError:
+        raise VATIDFinalError(error_messages['invalid'])
    try:
        transport = Transport(
            cache=SqliteCache(os.path.join(settings.CACHE_DIR, "validate_vat_id_ch_zeep_cache.db")),
@@ -113,6 +113,11 @@ def assign_automatically(event: Event, user_id: int=None, subevent_id: int=None)

        lock_objects(quotas, shared_lock_objects=[event])
        for wle in qs:
+            # add this event to wle.item as it is not yet cached and is needed in check_quotas
+            wle.item.event = event
+            if wle.variation:
+                wle.variation.item = wle.item
+
            if (wle.item_id, wle.variation_id, wle.subevent_id) in gone:
                continue
            ev = (wle.subevent or event)
@@ -76,11 +76,12 @@ from pretix.base.validators import multimail_validate
 from pretix.control.forms import (
    ExtFileField, FontSelect, MultipleLanguagesWidget, SingleLanguageWidget,
 )
-from pretix.helpers.countries import CachedCountries
+from pretix.helpers.countries import CachedCountries, pycountry_add

 ROUNDING_MODES = (
    ('line', _('Compute taxes for every line individually')),
    ('sum_by_net', _('Compute taxes based on net total')),
+    ('sum_by_net_only_business', _('For business customers, compute taxes based on net total. For individuals, use line-based rounding')),
    ('sum_by_net_keep_gross', _('Compute taxes based on net total with stable gross prices')),
    # We could also have sum_by_gross, but we're not aware of any use-cases for it
 )
@@ -180,6 +181,19 @@ DEFAULTS = {
            widget=forms.CheckboxInput(attrs={'data-display-dependency': '#id_settings-customer_accounts'}),
        )
    },
+    'customer_accounts_require_login_for_order_access': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Require login to access order confirmation pages"),
+            help_text=_("If enabled, users who were logged in at the time of purchase must also log in to access their order information. "
+                        "If a customer account is created while placing an order, the restriction only becomes active after the customer "
+                        "account is activated."),
+            widget=forms.CheckboxInput(attrs={'data-display-dependency': '#id_settings-customer_accounts'}),
+        )
+    },
    'customer_accounts_link_by_email': {
        'default': 'False',
        'type': bool,
@@ -629,13 +643,40 @@ DEFAULTS = {
        'form_kwargs': dict(
            label=_("Ask for VAT ID"),
            help_text=format_lazy(
-                _("Only works if an invoice address is asked for. VAT ID is never required and only requested from "
-                  "business customers in the following countries: {countries}"),
+                _("Only works if an invoice address is asked for. VAT ID is only requested from business customers "
+                  "in the following countries: {countries}."),
                countries=lazy(lambda *args: ', '.join(sorted(gettext(Country(cc).name) for cc in VAT_ID_COUNTRIES)), str)()
            ),
            widget=forms.CheckboxInput(attrs={'data-checkbox-dependency': '#id_invoice_address_asked'}),
        )
    },
+    'invoice_address_vatid_required_countries': {
+        'default': ['IT', 'GR'],
+        'type': list,
+        'form_class': forms.MultipleChoiceField,
+        'serializer_class': serializers.MultipleChoiceField,
+        'serializer_kwargs': dict(
+            choices=lazy(
+                lambda *args: sorted([(cc, gettext(Country(cc).name)) for cc in VAT_ID_COUNTRIES], key=lambda c: c[1]),
+                list
+            )(),
+        ),
+        'form_kwargs': dict(
+            label=_("Require VAT ID in"),
+            choices=lazy(
+                lambda *args: sorted([(cc, gettext(Country(cc).name)) for cc in VAT_ID_COUNTRIES], key=lambda c: c[1]),
+                list
+            )(),
+            help_text=format_lazy(
+                _("VAT ID is optional by default, because not all businesses are assigned a VAT ID in all countries. "
+                  "VAT ID will be required for all business addresses in the selected countries."),
+            ),
+            widget=forms.CheckboxSelectMultiple(attrs={
+                "class": "scrolling-multiple-choice",
+                'data-display-dependency': '#id_invoice_address_vatid'
+            }),
+        )
+    },
    'invoice_address_explanation_text': {
        'default': '',
        'type': LazyI18nString,
@@ -1185,6 +1226,15 @@ DEFAULTS = {
        'default': json.dumps(['web']),
        'type': list
    },
+    'invoice_generate_only_business': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Only issue invoices to business customers"),
+        )
+    },
    'invoice_address_from': {
        'default': '',
        'type': str,
@@ -2898,6 +2948,28 @@ If you did not request a new password, please ignore this email.

 Best regards,  

+Your {organizer} team"""))  # noqa: W291
+    },
+    'mail_subject_customer_security_notice': {
+        'type': LazyI18nString,
+        'default': LazyI18nString.from_gettext(gettext_noop("Changes to your account at {organizer}")),
+    },
+    'mail_text_customer_security_notice': {
+        'type': LazyI18nString,
+        'default': LazyI18nString.from_gettext(gettext_noop("""Hello {name},
+
+the following change has been made to your account at {organizer}:
+
+{message}
+
+You can review and change your account settings here:
+
+{url}
+
+If this change was not performed by you, please contact us immediately.
+
+Best regards,  
+
 Your {organizer} team"""))  # noqa: W291
    },
    'smtp_use_custom': {
@@ -3887,7 +3959,7 @@ COUNTRIES_WITH_STATE_IN_ADDRESS = {
    'MX': (['State', 'Federal district', 'Federal entity'], 'short'),
    'US': (['State', 'Outlying area', 'District'], 'short'),
    'IT': (['Province', 'Free municipal consortium', 'Metropolitan city', 'Autonomous province',
-            'Free municipal consortium', 'Decentralized regional entity'], 'short'),
+            'Decentralized regional entity'], 'short'),
 }
 COUNTRY_STATE_LABEL = {
    # Countries in which the "State" field should not be called "State"
@@ -3895,6 +3967,8 @@ COUNTRY_STATE_LABEL = {
    'JP': pgettext_lazy('address', 'Prefecture'),
    'IT': pgettext_lazy('address', 'Province'),
 }
+# Workaround for https://github.com/pretix/pretix/issues/5796
+pycountry_add(pycountry.subdivisions, code="IT-AO", country_code="IT", name="Valle d'Aosta", parent="23", parent_code="IT-23", type="Province")

 settings_hierarkey = Hierarkey(attribute_name='settings')

@@ -51,7 +51,7 @@ from pretix.api.serializers.waitinglist import WaitingListSerializer
 from pretix.base.i18n import LazyLocaleException
 from pretix.base.models import (
    CachedCombinedTicket, CachedTicket, Event, InvoiceAddress, OrderPayment,
-    OrderPosition, OrderRefund, QuestionAnswer,
+    OrderPosition, OrderRefund, OutgoingMail, QuestionAnswer,
 )
 from pretix.base.services.invoices import invoice_pdf_task
 from pretix.base.signals import register_data_shredders
@@ -329,6 +329,10 @@ class EmailAddressShredder(BaseDataShredder):
            sleep_time=2,
        )

+        slow_delete(
+            OutgoingMail.objects.filter(event=self.event)
+        )
+
        for o in _progress_helper(qs_orders, progress_callback, qs_op_cnt, total):
            changed = bool(o.email) or bool(o.customer)
            o.email = None
@@ -944,32 +944,40 @@ As with all event-plugin signals, the ``sender`` keyword argument will contain t

 email_filter = EventPluginSignal()
 """
-Arguments: ``message``, ``order``, ``user``
+Arguments: ``message``, ``order``, ``user``, ``outgoing_mail``

 This signal allows you to implement a middleware-style filter on all outgoing emails. You are expected to
 return a (possibly modified) copy of the message object passed to you.

 As with all event-plugin signals, the ``sender`` keyword argument will contain the event.
 The ``message`` argument will contain an ``EmailMultiAlternatives`` object.
+The ``outgoing_mail`` argument will contain the ``OutgoingMail`` model instance. Note that the ``message`` object
+might have newer information if a previous plugin already modified the email.
 If the email is associated with a specific order, the ``order`` argument will be passed as well, otherwise
 it will be ``None``.
 If the email is associated with a specific user, e.g. a notification email, the ``user`` argument will be passed as
 well, otherwise it will be ``None``.
+
+You can raise ``WithholdMailException`` to prevent the email from being sent, e.g. when implementing rate limiting.
 """

 global_email_filter = GlobalSignal()
 """
-Arguments: ``message``, ``order``, ``user``, ``customer``, ``organizer``
+Arguments: ``message``, ``order``, ``user``, ``customer``, ``organizer``, ``outgoing_mail``

 This signal allows you to implement a middleware-style filter on all outgoing emails. You are expected to
 return a (possibly modified) copy of the message object passed to you.

 This signal is called on all events and even if there is no known event. ``sender`` is an event or None.
 The ``message`` argument will contain an ``EmailMultiAlternatives`` object.
+The ``outgoing_mail`` argument will contain the ``OutgoingMail`` model instance. Note that the ``message`` object
+might have newer information if a previous plugin already modified the email.
 If the email is associated with a specific order, the ``order`` argument will be passed as well, otherwise
 it will be ``None``.
 If the email is associated with a specific user, e.g. a notification email, the ``user`` argument will be passed as
 well, otherwise it will be ``None``.
+
+You can raise ``WithholdMailException`` to prevent the email from being sent, e.g. when implementing rate limiting.
 """


@@ -8,9 +8,6 @@
        <h1>{% trans "Not found" %}</h1>
        <p>{% trans "I'm afraid we could not find the the resource you requested." %}</p>
        <p>{{ exception }}</p>
-        <p class="links">
-            <a id='goback' href='#'>{% trans "Take a step back" %}</a>
-        </p>
        {% if request.user.is_staff and not staff_session %}
            <form action="{% url 'control:user.sudo' %}?next={{ request.path|add:"?"|add:request.GET.urlencode|urlencode }}" method="post">
                <p>
@@ -0,0 +1,65 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020  Raphael Michel and contributors
+# Copyright (C) 2020-today pretix GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+from datetime import datetime
+
+from django import template
+from django.utils.html import format_html
+from django.utils.timezone import get_current_timezone
+
+from pretix.base.i18n import LazyExpiresDate
+from pretix.helpers.templatetags.date_fast import date_fast
+
+register = template.Library()
+
+
+@register.simple_tag
+def html_time(value: datetime, dt_format: str = "SHORT_DATE_FORMAT", **kwargs):
+    """
+    Building a <time datetime='{html-datetime}'>{human-readable datetime}</time> html string,
+    where the html-datetime as well as the human-readable datetime can be set
+    to a value from django's FORMAT_SETTINGS or "format_expires".
+
+    If attr_fmt isn’t provided, it will be set to isoformat.
+
+    Usage example:
+    {% html_time event_start "SHORT_DATETIME_FORMAT" %}
+    or
+    {% html_time event_start "TIME_FORMAT" attr_fmt="H:i" %}
+    """
+    if value in (None, ''):
+        return ''
+    value = value.astimezone(get_current_timezone())
+    attr_fmt = kwargs["attr_fmt"] if kwargs else None
+
+    try:
+        if not attr_fmt:
+            date_html = value.isoformat()
+        else:
+            date_html = date_fast(value, attr_fmt)
+
+        if dt_format == "format_expires":
+            date_human = LazyExpiresDate(value)
+        else:
+            date_human = date_fast(value, dt_format)
+        return format_html("<time datetime='{}'>{}</time>", date_html, date_human)
+    except AttributeError:
+        return ''
@@ -26,7 +26,8 @@ from babel.numbers import format_currency
 from django import template
 from django.conf import settings
 from django.template.defaultfilters import floatformat
-from django.utils import translation
+
+from pretix.base.i18n import get_babel_locale

 register = template.Library()

@@ -59,13 +60,10 @@ def money_filter(value: Decimal, arg='', hide_currency=False):
    if hide_currency:
        return floatformat(value, f"{places}g")

-    locale_parts = translation.get_language().split("-", 1)
-    locale = locale_parts[0]
-    if len(locale_parts) > 1 and len(locale_parts[1]) == 2:
-        try:
-            locale = Locale(locale_parts[0], locale_parts[1].upper())
-        except UnknownLocaleError:
-            pass
+    try:
+        locale = Locale(get_babel_locale())
+    except UnknownLocaleError:
+        locale = "en"

    try:
        return format_currency(value, arg, locale=locale)
@@ -32,13 +32,14 @@
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under the License.

+import html
 import re
 import urllib.parse

 import bleach
 import markdown
-from bleach import DEFAULT_CALLBACKS
-from bleach.linkifier import build_email_re, build_url_re
+from bleach import DEFAULT_CALLBACKS, html5lib_shim
+from bleach.linkifier import build_email_re
 from django import template
 from django.conf import settings
 from django.core import signing
@@ -124,6 +125,23 @@ ALLOWED_ATTRIBUTES = {

 ALLOWED_PROTOCOLS = {'http', 'https', 'mailto', 'tel'}

+
+def build_url_re(tlds=tld_set, protocols=html5lib_shim.allowed_protocols):
+    # Differs from bleach regex by allowing { and } in URL to allow placeholders in URL parameters
+    return re.compile(
+        r"""\(*  # Match any opening parentheses.
+        \b(?<![@.])(?:(?:{0}):/{{0,3}}(?:(?:\w+:)?\w+@)?)?  # http://
+        ([\w-]+\.)+(?:{1})(?:\:[0-9]+)?(?!\.\w)\b   # xx.yy.tld(:##)?
+        (?:[/?][^\s\|\\\^`<>"]*)?
+            # /path/zz (excluding "unsafe" chars from RFC 3986,
+            # except for # and ~, which happen in practice)
+        """.format(
+            "|".join(sorted(protocols)), "|".join(sorted(tlds))
+        ),
+        re.IGNORECASE | re.VERBOSE | re.UNICODE,
+    )
+
+
 URL_RE = SimpleLazyObject(lambda: build_url_re(tlds=sorted(tld_set, key=len, reverse=True)))

 EMAIL_RE = SimpleLazyObject(lambda: build_email_re(tlds=sorted(tld_set, key=len, reverse=True)))
@@ -138,7 +156,7 @@ def safelink_callback(attrs, new=False):
    Makes sure that all links to a different domain are passed through a redirection handler
    to ensure there's no passing of referers with secrets inside them.
    """
-    url = attrs.get((None, 'href'), '/')
+    url = html.unescape(attrs.get((None, 'href'), '/'))
    if not url_has_allowed_host_and_scheme(url, allowed_hosts=None) and not url.startswith('mailto:') and not url.startswith('tel:'):
        signer = signing.Signer(salt='safe-redirect')
        attrs[None, 'href'] = reverse('redirect') + '?url=' + urllib.parse.quote(signer.sign(url))
@@ -333,8 +351,14 @@ def markdown_compile_email(source, allowed_tags=None, allowed_attributes=ALLOWED
        # This is a workaround to fix placeholders in URL targets
        def context_callback(attrs, new=False):
            if (None, "href") in attrs and "{" in attrs[None, "href"]:
-                # Do not use MODE_RICH_TO_HTML to avoid recursive linkification
-                attrs[None, "href"] = escape(format_map(attrs[None, "href"], context=context, mode=SafeFormatter.MODE_RICH_TO_PLAIN))
+                # Do not use MODE_RICH_TO_HTML to avoid recursive linkification.
+                # We want to esacpe the end result, however, we need to unescape the input to prevent & being turned
+                # to &amp;amp; because the input is already escaped by the markdown parser.
+                attrs[None, "href"] = escape(format_map(
+                    html.unescape(attrs[None, "href"]),
+                    context=context,
+                    mode=SafeFormatter.MODE_RICH_TO_PLAIN
+                ))
            return attrs

        context_callbacks.append(context_callback)
@@ -93,7 +93,9 @@ def timeline_for_event(event, subevent=None):
        description=format_lazy(
            '{} ({})',
            pgettext_lazy('timeline', 'End of ticket sales'),
-            pgettext_lazy('timeline', 'automatically because the event is over and no end of presale has been configured') if not ev.presale_end else ""
+            pgettext_lazy('timeline', 'automatically because the event is over and no end of presale has been configured')
+        ) if not ev.presale_end else (
+            pgettext_lazy('timeline', 'End of ticket sales')
        ),
        edit_url=ev_edit_url + '#id_presale_end_0'
    ))
@@ -95,6 +95,7 @@ class OrganizerSlugBanlistValidator(BanlistValidator):
        'csp_report',
        'widget',
        'lead',
+        'scheduling',
    ]


@@ -36,9 +36,8 @@ class DownloadView(TemplateView):
    def object(self) -> CachedFile:
        try:
            o = get_object_or_404(CachedFile, id=self.kwargs['id'], web_download=True)
-            if o.session_key:
-                if o.session_key != self.request.session.session_key:
-                    raise Http404()
+            if not o.allowed_for_session(self.request):
+                raise Http404()
            return o
        except (ValueError, ValidationError):   # Invalid URLs
            raise Http404()
@@ -20,15 +20,17 @@
 # <https://www.gnu.org/licenses/>.
 #
 import pycountry
+from django.conf import settings
 from django.http import JsonResponse
 from django.shortcuts import get_object_or_404
-from django.utils.translation import pgettext
+from django.utils.translation import gettext, pgettext, pgettext_lazy
 from django_countries.fields import Country
 from django_scopes import scope

 from pretix.base.addressvalidation import (
    COUNTRIES_WITH_STREET_ZIPCODE_AND_CITY_REQUIRED,
 )
+from pretix.base.i18n import language
 from pretix.base.invoicing.transmission import get_transmission_types
 from pretix.base.models import Organizer
 from pretix.base.models.tax import VAT_ID_COUNTRIES
@@ -36,6 +38,28 @@ from pretix.base.settings import (
    COUNTRIES_WITH_STATE_IN_ADDRESS, COUNTRY_STATE_LABEL,
 )

+VAT_ID_LABELS = {
+    # VAT ID is a EU concept and Switzerland has a distinct, but differently-named concept
+    # Translators: Only translate to French (IDE) and Italien (IDI), otherwise keep the same
+    "CH": pgettext_lazy("tax_id_swiss", "UID"),
+
+    # Awareness around VAT IDs differes by EU country. For example, in Germany the VAT ID is assigned
+    # separately to each company and only used in cross-country transactions. Therefore, it makes sense
+    # to call it just "VAT ID" on the form, and people will either know their VAT ID or they don't.
+    # In contrast, in Italy the EU-compatible VAT ID is not separately assigned, but is just "IT" + the national tax
+    # number (Partita IVA) and also used on domestic transactions. So someone who never purchased something international
+    # for their company, might still know the value, if we call it the right way and not just "VAT ID".
+
+    # Translators: Translate to only "P.IVA" in Italian, keep second part as-is in other languages
+    "IT": pgettext_lazy("tax_id_italy", "VAT ID / P.IVA"),
+    # Translators: Translate to only "ΑΦΜ" in Greek
+    "GR": pgettext_lazy("tax_id_greece", "VAT ID / TIN"),
+    # Translators: Translate to only "NIF" in Spanish
+    "ES": pgettext_lazy("tax_id_spain", "VAT ID / NIF"),
+    # Translators: Translate to only "NIF" in Portuguese
+    "PT": pgettext_lazy("tax_id_portugal", "VAT ID / NIF"),
+}
+

 def _info(cc):
    info = {
@@ -47,7 +71,12 @@ def _info(cc):
            'required': 'if_any' if cc in COUNTRIES_WITH_STATE_IN_ADDRESS else False,
            'label': COUNTRY_STATE_LABEL.get(cc, pgettext('address', 'State')),
        },
-        'vat_id': {'visible': cc in VAT_ID_COUNTRIES, 'required': False},
+        'vat_id': {
+            'visible': cc in VAT_ID_COUNTRIES,
+            'required': False,
+            'label': VAT_ID_LABELS.get(cc, gettext("VAT ID")),
+            'helptext_visible': True,
+        },
    }
    if cc not in COUNTRIES_WITH_STATE_IN_ADDRESS:
        return {'data': [], **info}
@@ -55,14 +84,14 @@ def _info(cc):
    statelist = [s for s in pycountry.subdivisions.get(country_code=cc) if s.type in types]
    return {
        'data': [
-            {'name': s.name, 'code': s.code[3:]}
+            {'name': gettext(s.name), 'code': s.code[3:]}
            for s in sorted(statelist, key=lambda s: s.name)
        ],
        **info,
    }


-def address_form(request):
+def _address_form(request):
    cc = request.GET.get("country", "DE")
    info = _info(cc)

@@ -82,7 +111,7 @@ def address_form(request):
            for t in get_transmission_types():
                if t.is_available(event=event, country=country, is_business=is_business):
                    result = {"name": str(t.public_name), "code": t.identifier}
-                    if t.exclusive:
+                    if t.is_exclusive(event=event, country=country, is_business=is_business):
                        info["transmission_types"] = [result]
                        break
                    else:
@@ -124,4 +153,21 @@ def address_form(request):
                        "required": transmission_type.identifier == selected_transmission_type and k in required
                    }

+            if is_business and country in event.settings.invoice_address_vatid_required_countries and info["vat_id"]["visible"]:
+                info["vat_id"]["required"] = True
+            if info["vat_id"]["required"]:
+                # The help text explains that it is optional, so we want to hide that if it is required
+                info["vat_id"]["helptext_visible"] = False
+
+    return info
+
+
+def address_form(request):
+    locale = request.GET.get('locale')
+    if locale in dict(settings.LANGUAGES):
+        with language(locale):
+            info = _address_form(request)
+    else:
+        info = _address_form(request)
+
    return JsonResponse(info)
@@ -45,7 +45,7 @@ from django.core.exceptions import NON_FIELD_ERRORS, ValidationError
 from django.db.models import Prefetch, Q, prefetch_related_objects
 from django.forms import formset_factory, inlineformset_factory
 from django.urls import reverse
-from django.utils.functional import cached_property
+from django.utils.functional import cached_property, lazy
 from django.utils.html import escape, format_html
 from django.utils.safestring import mark_safe
 from django.utils.timezone import get_current_timezone_name
@@ -53,7 +53,7 @@ from django.utils.translation import gettext, gettext_lazy as _, pgettext_lazy
 from django_countries.fields import LazyTypedChoiceField
 from django_scopes.forms import SafeModelMultipleChoiceField
 from i18nfield.forms import (
-    I18nForm, I18nFormField, I18nFormSetMixin, I18nTextInput,
+    I18nForm, I18nFormField, I18nFormSetMixin, I18nTextarea, I18nTextInput,
 )
 from pytz import common_timezones

@@ -207,6 +207,7 @@ class EventWizardBasicsForm(I18nModelForm):
            'Sample Conference Center\nHeidelberg, Germany'
        )
        self.fields['slug'].widget.prefix = build_absolute_uri(self.organizer, 'presale:organizer.index')
+        self.fields['tax_rate']._required = True  # Do not render as optional because it is conditionally required
        if self.has_subevents:
            del self.fields['presale_start']
            del self.fields['presale_end']
@@ -866,6 +867,11 @@ class TaxSettingsForm(EventSettingsValidationMixin, SettingsForm):
                "The gross price of some products may be changed to ensure correct rounding, while the net "
                "prices will be kept as configured. This may cause the actual payment amount to differ."
            ),
+            "sum_by_net_only_business": _(
+                "Same as above, but only applied to business customers. Line-based rounding will be used for consumers. "
+                "Recommended when e-invoicing is only used for business customers and consumers do not receive "
+                "invoices. This can cause the payment amount to change when the invoice address is changed."
+            ),
            "sum_by_net_keep_gross": _(
                "Recommended for e-invoicing when you primarily sell to consumers. "
                "The gross or net price of some products may be changed automatically to ensure correct "
@@ -927,6 +933,7 @@ class InvoiceSettingsForm(EventSettingsValidationMixin, SettingsForm):
        'invoice_address_asked',
        'invoice_address_required',
        'invoice_address_vatid',
+        'invoice_address_vatid_required_countries',
        'invoice_address_company_required',
        'invoice_address_beneficiary',
        'invoice_address_custom_field',
@@ -937,6 +944,7 @@ class InvoiceSettingsForm(EventSettingsValidationMixin, SettingsForm):
        'invoice_show_payments',
        'invoice_reissue_after_modify',
        'invoice_generate',
+        'invoice_generate_only_business',
        'invoice_period',
        'invoice_attendee_name',
        'invoice_event_location',
@@ -1309,9 +1317,17 @@ class MailSettingsForm(FormPlaceholderMixin, SettingsForm):
    mail_text_order_invoice = I18nFormField(
        label=_("Text"),
        required=False,
-        widget=I18nMarkdownTextarea,
-        help_text=_("This will only be used if the invoice is sent to a different email address or at a different time "
-                    "than the order confirmation."),
+        widget=I18nTextarea,  # no Markdown supported
+        help_text=lazy(
+            lambda: str(_(
+                "This will only be used if the invoice is sent to a different email address or at a different time "
+                "than the order confirmation."
+            )) + " " + str(_(
+                "Formatting is not supported, as some accounting departments process mail automatically and do not "
+                "handle formatted emails properly."
+            )),
+            str
+        )()
    )
    mail_subject_download_reminder = I18nFormField(
        label=_("Subject sent to order contact address"),
@@ -1479,6 +1495,9 @@ class MailSettingsForm(FormPlaceholderMixin, SettingsForm):
        'mail_subject_resend_all_links': ['event', 'orders'],
        'mail_attach_ical_description': ['event', 'event_or_subevent'],
    }
+    plain_rendering = {
+        'mail_text_order_invoice',
+    }

    def __init__(self, *args, **kwargs):
        self.event = event = kwargs.get('obj')
@@ -1497,7 +1516,7 @@ class MailSettingsForm(FormPlaceholderMixin, SettingsForm):
        self.event.meta_values_cached = self.event.meta_values.select_related('property').all()

        for k, v in self.base_context.items():
-            self._set_field_placeholders(k, v, rich=k.startswith('mail_text_'))
+            self._set_field_placeholders(k, v, rich=k.startswith('mail_text_') and k not in self.plain_rendering)

        for k, v in list(self.fields.items()):
            if k.endswith('_attendee') and not event.settings.attendee_emails_asked:
@@ -1957,6 +1976,13 @@ class EventFooterLinkForm(I18nModelForm):
    class Meta:
        model = EventFooterLink
        fields = ('label', 'url')
+        widgets = {
+            "url": forms.URLInput(
+                attrs={
+                    "placeholder": "https://..."
+                }
+            )
+        }


 class BaseEventFooterLinkFormSet(I18nFormSetMixin, forms.BaseInlineFormSet):
@@ -57,10 +57,15 @@ from pretix.base.forms.widgets import (
 from pretix.base.models import (
    Checkin, CheckinList, Device, Event, EventMetaProperty, EventMetaValue,
    Gate, Invoice, InvoiceAddress, Item, Order, OrderPayment, OrderPosition,
-    OrderRefund, Organizer, Question, QuestionAnswer, Quota, SalesChannel,
-    SubEvent, SubEventMetaValue, Team, TeamAPIToken, TeamInvite, Voucher,
+    OrderRefund, Organizer, OutgoingMail, Question, QuestionAnswer, Quota,
+    SalesChannel, SubEvent, SubEventMetaValue, Team, TeamAPIToken, TeamInvite,
+    Voucher,
 )
 from pretix.base.signals import register_payment_providers
+from pretix.base.timeframes import (
+    DateFrameField,
+    resolve_timeframe_to_datetime_start_inclusive_end_exclusive,
+)
 from pretix.control.forms import SplitDateTimeField
 from pretix.control.forms.widgets import Select2, Select2ItemVarQuota
 from pretix.control.signals import order_search_filter_q
@@ -1219,6 +1224,129 @@ class OrderPaymentSearchFilterForm(forms.Form):
        return qs


+class QuestionAnswerFilterForm(forms.Form):
+    STATUS_VARIANTS = [
+        ("", _("All orders")),
+        (Order.STATUS_PAID, _("Paid")),
+        (Order.STATUS_PAID + 'v', _("Paid or confirmed")),
+        (Order.STATUS_PENDING, _("Pending")),
+        (Order.STATUS_PENDING + Order.STATUS_PAID, _("Pending or paid")),
+        ("o", _("Pending (overdue)")),
+        (Order.STATUS_EXPIRED, _("Expired")),
+        (Order.STATUS_PENDING + Order.STATUS_EXPIRED, _("Pending or expired")),
+        (Order.STATUS_CANCELED, _("Canceled"))
+    ]
+
+    status = forms.ChoiceField(
+        choices=STATUS_VARIANTS,
+        required=False,
+        label=_("Order status"),
+    )
+    item = forms.ChoiceField(
+        choices=[],
+        required=False,
+        label=_("Products"),
+    )
+    subevent = forms.ModelChoiceField(
+        queryset=SubEvent.objects.none(),
+        required=False,
+        empty_label=pgettext_lazy('subevent', 'All dates'),
+        label=pgettext_lazy("subevent", "Date"),
+    )
+    date_range = DateFrameField(
+        required=False,
+        include_future_frames=True,
+        label=_('Event date'),
+    )
+
+    def __init__(self, *args, **kwargs):
+        self.event = kwargs.pop('event')
+        super().__init__(*args, **kwargs)
+        self.initial['status'] = Order.STATUS_PENDING + Order.STATUS_PAID
+
+        choices = [('', _('All products'))]
+        for i in self.event.items.prefetch_related('variations').all():
+            variations = list(i.variations.all())
+            if variations:
+                choices.append((str(i.pk), _('{product} – Any variation').format(product=str(i))))
+                for v in variations:
+                    choices.append(('%d-%d' % (i.pk, v.pk), '%s – %s' % (str(i), v.value)))
+            else:
+                choices.append((str(i.pk), str(i)))
+        self.fields['item'].choices = choices
+
+        if self.event.has_subevents:
+            self.fields["subevent"].queryset = self.event.subevents.all()
+            self.fields['subevent'].widget = Select2(
+                attrs={
+                    'data-model-select2': 'event',
+                    'data-select2-url': reverse('control:event.subevents.select2', kwargs={
+                        'event': self.event.slug,
+                        'organizer': self.event.organizer.slug,
+                    }),
+                    'data-placeholder': pgettext_lazy('subevent', 'All dates')
+                }
+            )
+            self.fields['subevent'].widget.choices = self.fields['subevent'].choices
+        else:
+            del self.fields['subevent']
+
+    def clean(self):
+        cleaned_data = super().clean()
+        subevent = cleaned_data.get('subevent')
+        date_range = cleaned_data.get('date_range')
+
+        if subevent is not None and date_range is not None:
+            d_start, d_end = resolve_timeframe_to_datetime_start_inclusive_end_exclusive(now(), date_range, self.event.timezone)
+            if (
+                (d_start and not (d_start <= subevent.date_from)) or
+                (d_end and not (subevent.date_from < d_end))
+            ):
+                self.add_error('subevent', pgettext_lazy('subevent', "Date doesn't start in selected date range."))
+        return cleaned_data
+
+    def filter_qs(self, opqs):
+        fdata = self.cleaned_data
+
+        subevent = fdata.get('subevent', None)
+        date_range = fdata.get('date_range', None)
+
+        if subevent is not None:
+            opqs = opqs.filter(subevent=subevent)
+
+        if date_range is not None:
+            d_start, d_end = resolve_timeframe_to_datetime_start_inclusive_end_exclusive(now(), date_range, self.event.timezone)
+            if d_start:
+                opqs = opqs.filter(subevent__date_from__gte=d_start)
+            if d_end:
+                opqs = opqs.filter(subevent__date_from__lt=d_end)
+
+        s = fdata.get("status", Order.STATUS_PENDING + Order.STATUS_PAID)
+        if s != "":
+            if s == Order.STATUS_PENDING:
+                opqs = opqs.filter(order__status=Order.STATUS_PENDING,
+                                   order__expires__lt=now().replace(hour=0, minute=0, second=0))
+            elif s == Order.STATUS_PENDING + Order.STATUS_PAID:
+                opqs = opqs.filter(order__status__in=[Order.STATUS_PENDING, Order.STATUS_PAID])
+            elif s == Order.STATUS_PAID + 'v':
+                opqs = opqs.filter(
+                    Q(order__status=Order.STATUS_PAID) |
+                    Q(order__status=Order.STATUS_PENDING, order__valid_if_pending=True)
+                )
+            elif s == Order.STATUS_PENDING + Order.STATUS_EXPIRED:
+                opqs = opqs.filter(order__status__in=[Order.STATUS_PENDING, Order.STATUS_EXPIRED])
+            else:
+                opqs = opqs.filter(order__status=s)
+
+        if s not in (Order.STATUS_CANCELED, ""):
+            opqs = opqs.filter(canceled=False)
+        if fdata.get("item", "") != "":
+            i = fdata.get("item", "")
+            opqs = opqs.filter(item_id__in=(i,))
+
+        return opqs
+
+
 class SubEventFilterForm(FilterForm):
    orders = {
        'date_from': 'date_from',
@@ -2688,3 +2816,61 @@ class DeviceFilterForm(FilterForm):
            qs = qs.order_by('-device_id')

        return qs
+
+
+class OutgoingMailFilterForm(FilterForm):
+    orders = {
+        'date': 'created',
+        '-date': '-created',
+    }
+    query = forms.CharField(
+        label=_('Search email address or subject'),
+        widget=forms.TextInput(attrs={
+            'placeholder': _('Search email address or subject'),
+        }),
+        required=False
+    )
+    event = forms.ModelChoiceField(
+        queryset=Event.objects.none(),
+        label=_('Event'),
+        empty_label=_('All events'),
+        required=False,
+    )
+    status = forms.ChoiceField(
+        label=_('Status'),
+        choices=[
+            ('', _('All')),
+            *OutgoingMail.STATUS_CHOICES,
+        ],
+        required=False
+    )
+
+    def __init__(self, *args, **kwargs):
+        request = kwargs.pop('request')
+        super().__init__(*args, **kwargs)
+        self.fields['event'].queryset = request.organizer.events.all()
+
+    def filter_qs(self, qs):
+        fdata = self.cleaned_data
+
+        if fdata.get('query'):
+            query = fdata.get('query')
+            qs = qs.filter(
+                Q(to__containsstring=query.lower())
+                | Q(cc__containsstring=query.lower())
+                | Q(bcc__containsstring=query.lower())
+                | Q(subject__icontains=query)
+            )
+
+        if fdata.get('event'):
+            qs = qs.filter(event=fdata['event'])
+
+        if fdata.get('status'):
+            qs = qs.filter(status=fdata['status'])
+
+        if fdata.get('ordering'):
+            qs = qs.order_by(self.get_order_by())
+        else:
+            qs = qs.order_by("-created", "-pk")
+
+        return qs
@@ -974,7 +974,7 @@ class EventCancelForm(FormPlaceholderMixin, forms.Form):
        self._set_field_placeholders('send_subject', ['event_or_subevent', 'refund_amount', 'position_or_address',
                                                      'order', 'event'])
        self._set_field_placeholders('send_message', ['event_or_subevent', 'refund_amount', 'position_or_address',
-                                                      'order', 'event'])
+                                                      'order', 'event'], rich=True)
        self.fields['send_waitinglist_subject'] = I18nFormField(
            label=_("Subject"),
            required=True,
@@ -998,7 +998,7 @@ class EventCancelForm(FormPlaceholderMixin, forms.Form):
            ))
        )
        self._set_field_placeholders('send_waitinglist_subject', ['event_or_subevent', 'event'])
-        self._set_field_placeholders('send_waitinglist_message', ['event_or_subevent', 'event'])
+        self._set_field_placeholders('send_waitinglist_message', ['event_or_subevent', 'event'], rich=True)

        if self.event.has_subevents:
            self.fields['subevent'].queryset = self.event.subevents.all()
@@ -474,6 +474,7 @@ class OrganizerSettingsForm(SettingsForm):
        'customer_accounts',
        'customer_accounts_native',
        'customer_accounts_link_by_email',
+        'customer_accounts_require_login_for_order_access',
        'invoice_regenerate_allowed',
        'contact_mail',
        'imprint_url',
@@ -584,6 +585,7 @@ class MailSettingsForm(SettingsForm):
        help_text=''.join([
            str(_("All emails will be sent to this address as a Bcc copy.")),
            str(_("You can specify multiple recipients separated by commas.")),
+            str(_("Sensitive emails like password resets will not be sent in Bcc.")),
        ]),
        validators=[multimail_validate],
        required=False,
@@ -633,6 +635,16 @@ class MailSettingsForm(SettingsForm):
        required=False,
        widget=I18nMarkdownTextarea,
    )
+    mail_subject_customer_security_notice = I18nFormField(
+        label=_("Subject"),
+        required=False,
+        widget=I18nTextInput,
+    )
+    mail_text_customer_security_notice = I18nFormField(
+        label=_("Text"),
+        required=False,
+        widget=I18nMarkdownTextarea,
+    )

    base_context = {
        'mail_text_customer_registration': ['customer', 'url'],
@@ -641,6 +653,8 @@ class MailSettingsForm(SettingsForm):
        'mail_subject_customer_email_change': ['customer', 'url'],
        'mail_text_customer_reset': ['customer', 'url'],
        'mail_subject_customer_reset': ['customer', 'url'],
+        'mail_text_customer_security_notice': ['customer', 'url', 'message'],
+        'mail_subject_customer_security_notice': ['customer', 'url', 'message'],
    }

    def _get_sample_context(self, base_parameters):
@@ -654,6 +668,9 @@ class MailSettingsForm(SettingsForm):
                'presale:organizer.customer.activate'
            ) + '?token=' + get_random_string(30)

+        if 'message' in base_parameters:
+            placeholders['message'] = _('Your password has been changed.')
+
        if 'customer' in base_parameters:
            placeholders['name'] = pgettext_lazy('person_name_sample', 'John Doe')
            name_scheme = PERSON_NAME_SCHEMES[self.organizer.settings.name_scheme]
@@ -1024,6 +1041,13 @@ class OrganizerFooterLinkForm(I18nModelForm):
    class Meta:
        model = OrganizerFooterLink
        fields = ('label', 'url')
+        widgets = {
+            "url": forms.URLInput(
+                attrs={
+                    "placeholder": "https://..."
+                }
+            )
+        }


 class BaseOrganizerFooterLinkFormSet(I18nFormSetMixin, forms.BaseInlineFormSet):
@@ -170,6 +170,12 @@ class OrderFeeAdded(OrderChangeLogEntryType):
    plain = _('A fee has been added')


+@log_entry_types.new()
+class OrderRecomputed(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.recomputed'
+    plain = _('Taxes and rounding have been recomputed')
+
+
@log_entry_types.new()
 class OrderFeeChanged(OrderChangeLogEntryType):
    action_type = 'pretix.event.order.changed.feevalue'
@@ -699,6 +705,8 @@ class CoreUserImpersonatedLogEntryType(UserImpersonatedLogEntryType):
    'pretix.organizer.export.schedule.deleted': _('A scheduled export has been deleted.'),
    'pretix.organizer.export.schedule.executed': _('A scheduled export has been executed.'),
    'pretix.organizer.export.schedule.failed': _('A scheduled export has failed: {reason}.'),
+    'pretix.organizer.outgoingmails.retried': _('Failed emails have been scheduled to be retried.'),
+    'pretix.organizer.outgoingmails.aborted': _('Queued emails have been aborted.'),
    'pretix.giftcards.acceptance.added': _('Gift card acceptance for another organizer has been added.'),
    'pretix.giftcards.acceptance.removed': _('Gift card acceptance for another organizer has been removed.'),
    'pretix.giftcards.acceptance.acceptor.invited': _('A new gift card acceptor has been invited.'),
@@ -793,6 +801,8 @@ class CoreUserImpersonatedLogEntryType(UserImpersonatedLogEntryType):
    'pretix.giftcards.created': _('The gift card has been created.'),
    'pretix.giftcards.modified': _('The gift card has been changed.'),
    'pretix.giftcards.transaction.manual': _('A manual transaction has been performed.'),
+    'pretix.giftcards.transaction.payment': _('A payment has been performed.'),
+    'pretix.giftcards.transaction.refund': _('A refund has been performed. '),
    'pretix.team.token.created': _('The token "{name}" has been created.'),
    'pretix.team.token.deleted': _('The token "{name}" has been revoked.'),
    'pretix.event.checkin.reset': _('The check-in and print log state has been reset.')
@@ -814,7 +824,7 @@ class OrganizerPluginStateLogEntryType(LogEntryType):
            if app and hasattr(app, 'PretixPluginMeta'):
                return {
                    'href': reverse('control:organizer.settings.plugins', kwargs={
-                        'organizer': logentry.event.organizer.slug,
+                        'organizer': logentry.organizer.slug,
                    }) + '#plugin_' + logentry.parsed_data['plugin'],
                    'val': app.PretixPluginMeta.name
                }
@@ -679,6 +679,15 @@ def get_organizer_navigation(request):
            'active': (url.url_name == 'organizer.datasync.failedjobs'),
        }])

+        nav.append({
+            'label': _('Outgoing emails'),
+            'url': reverse('control:organizer.outgoingmails', kwargs={
+                'organizer': request.organizer.slug,
+            }),
+            'active': 'organizer.outgoingmail' in url.url_name,
+            'icon': 'send',
+        })
+
    merge_in(nav, sorted(
        sum((list(a[1]) for a in nav_organizer.send(request.organizer, request=request, organizer=request.organizer)),
            []),
@@ -126,7 +126,9 @@
                    {% endif %}
                    <a class="navbar-brand" href="{% url "control:index" %}">
                        <img src="{% static "pretixbase/img/pretix-icon-white-mini.svg" %}" />
-                        {{ settings.PRETIX_INSTANCE_NAME }}
+                        <span>
+                            {{ settings.PRETIX_INSTANCE_NAME }}
+                        </span>
                    </a>
                </div>
                <ul class="nav navbar-nav navbar-top-links navbar-left flip hidden-xs">
@@ -55,7 +55,7 @@
                <div class="col-md-2">
                    {% bootstrap_field formset.empty_form.overwrite layout='inline' form_group_class="" %}
                </div>
-                {{ f.value_map.as_hidden }}
+                {{ formset.empty_form.value_map.as_hidden }}
                <div class="col-md-2 text-right flip">
                    <i class="fa fa-warning hidden" data-toggle="tooltip" title=""></i>
                    <button type="button" class="btn btn-default hidden" data-edit-value-map data-toggle="modal"
@@ -12,6 +12,7 @@
                <legend>{% trans "Invoice generation" %}</legend>
                {% bootstrap_field form.invoice_generate layout="control" %}
                {% bootstrap_field form.invoice_generate_sales_channels layout="control" %}
+                {% bootstrap_field form.invoice_generate_only_business layout="control" %}
                {% bootstrap_field form.invoice_email_attachment layout="control" %}
                {% bootstrap_field form.invoice_email_organizer layout="control" %}
                {% bootstrap_field form.invoice_language layout="control" %}
@@ -43,6 +44,7 @@
                {% bootstrap_field form.invoice_name_required layout="control" %}
                {% bootstrap_field form.invoice_address_company_required layout="control" %}
                {% bootstrap_field form.invoice_address_vatid layout="control" %}
+                {% bootstrap_field form.invoice_address_vatid_required_countries layout="control" %}
                {% bootstrap_field form.invoice_address_beneficiary layout="control" %}
                {% bootstrap_field form.invoice_address_not_asked_free layout="control" %}
                {% bootstrap_field form.invoice_address_custom_field layout="control" %}
@@ -110,11 +112,6 @@
                                            <span class="text-success">
                                                <span class="fa fa-check fa-fw"></span>
                                                {% trans "Available" %}
-                                                {% if t.exclusive %}
-                                                    <span data-toggle="tooltip" title="{% trans "When this type is available for an invoice address, no other type can be selected." %}">
-                                                        {% trans "(exclusive)" %}
-                                                    </span>
-                                                {% endif %}
                                            </span>
                                        {% else %}
                                            <span class="text-muted">
@@ -20,35 +20,20 @@
        </div>
        <form class="panel-body filter-form" action="" method="get">
            <div class="row">
-                <div class="col-lg-2 col-sm-6 col-xs-6">
-                    <select name="status" class="form-control">
-                        <option value="" {% if request.GET.status == "" %}selected="selected"{% endif %}>{% trans "All orders" %}</option>
-                        <option value="p" {% if request.GET.status == "p" %}selected="selected"{% endif %}>{% trans "Paid" %}</option>
-                        <option value="pv" {% if request.GET.status == "pv" %}selected="selected"{% endif %}>{% trans "Paid or confirmed" %}</option>
-                        <option value="n" {% if request.GET.status == "n" %}selected="selected"{% endif %}>{% trans "Pending" %}</option>
-                        <option value="np" {% if request.GET.status == "np" or "status" not in request.GET %}selected="selected"{% endif %}>{% trans "Pending or paid" %}</option>
-                        <option value="o" {% if request.GET.status == "o" %}selected="selected"{% endif %}>{% trans "Pending (overdue)" %}</option>
-                        <option value="e" {% if request.GET.status == "e" %}selected="selected"{% endif %}>{% trans "Expired" %}</option>
-                        <option value="ne" {% if request.GET.status == "ne" %}selected="selected"{% endif %}>{% trans "Pending or expired" %}</option>
-                        <option value="c" {% if request.GET.status == "c" %}selected="selected"{% endif %}>{% trans "Canceled" %}</option>
-                    </select>
+                 <div class="col-md-2 col-xs-6">
+                     {% bootstrap_field form.status %}
+                 </div>
+                 <div class="col-md-3 col-xs-6">
+                     {% bootstrap_field form.item %}
+                 </div>
+            {% if has_subevents %}
+                <div class="col-md-3 col-xs-6">
+                    {% bootstrap_field form.subevent %}
                </div>
-                <div class="col-lg-5 col-sm-6 col-xs-6">
-                    <select name="item" class="form-control">
-                        <option value="">{% trans "All products" %}</option>
-                        {% for item in items %}
-                            <option value="{{ item.id }}"
-                                    {% if request.GET.item|add:0 == item.id %}selected="selected"{% endif %}>
-                                {{ item.name }}
-                            </option>
-                        {% endfor %}
-                    </select>
+                <div class="col-md-4 col-xs-6">
+                    {% bootstrap_field form.date_range %}
                </div>
-                {% if request.event.has_subevents %}
-                    <div class="col-lg-5 col-sm-6 col-xs-6">
-                        {% include "pretixcontrol/event/fragment_subevent_choice_simple.html" %}
-                    </div>
-                {% endif %}
+            {% endif %}
            </div>
            <div class="text-right">
                <button class="btn btn-primary btn-lg" type="submit">
@@ -353,7 +353,7 @@
                                                            data-toggle="tooltip"
                                                            title="{% trans 'Generate a cancellation document for this invoice and create a new invoice with a new invoice number.' %}"
                                                        {% endif %}>
-                                                    {% if order.status == "c" %}
+                                                    {% if order.status == "c" or not invoice_qualified %}
                                                        {% trans "Generate cancellation" %}
                                                    {% else %}
                                                        {% trans "Cancel and reissue" %}
@@ -22,7 +22,7 @@
                                {{ s.owner.fullname|default:s.owner.email }}
                            </span>
                        </div>
-                        <div class="col-lg-5 col-md-6 col-xs-12">
+                        <div class="col-lg-4 col-md-5 col-xs-12">
                            {% if s.schedule_next_run %}
                                <span class="fa fa-clock-o fa-fw"></span>
                                {% trans "Next run:" %}
@@ -53,7 +53,7 @@
                                {{ s.mail_subject }}
                            </span>
                        </div>
-                        <div class="col-lg-2 col-md-2 col-xs-12 text-right">
+                        <div class="col-lg-3 col-md-3 col-xs-12 text-right">
                            <form action="{% url "control:event.orders.export.do" event=request.event.slug organizer=request.organizer.slug %}"
                                  method="post" class="form-horizontal" data-asynctask data-asynctask-download
                                  data-asynctask-long>
@@ -73,6 +73,9 @@
                                    <a href="?identifier={{ s.export_identifier }}&scheduled={{ s.pk }}" class="btn btn-default" title="{% trans "Edit" %}" data-toggle="tooltip">
                                        <span class="fa fa-edit"></span>
                                    </a>
+                                    <a href="?identifier={{ s.export_identifier }}&scheduled_copy_from={{ s.pk }}" class="btn btn-default" title="{% trans "Copy" %}" data-toggle="tooltip">
+                                        <span class="fa fa-copy"></span>
+                                    </a>
                                {% endif %}
                                <a href="{% url "control:event.orders.export.scheduled.delete" event=request.event.slug organizer=request.event.organizer.slug pk=s.pk %}" class="btn btn-danger" title="{% trans "Delete" %}" data-toggle="tooltip">
                                    <span class="fa fa-trash"></span>
@@ -42,7 +42,11 @@
            <div class="form-group submit-group">
                <button formaction="{{ request.get_full_path }}" name="schedule" value="save" type="submit"
                        class="btn btn-primary btn-save" data-no-asynctask>
-                    {% trans "Save" %}
+                    {% if scheduled_copy_from %}
+                        {% trans "Save copy" %}
+                    {% else %}
+                        {% trans "Save" %}
+                    {% endif %}
                </button>
            </div>
        {% else %}
@@ -132,6 +132,7 @@
                        <legend>{% trans "Customer accounts" %}</legend>
                        {% bootstrap_field sform.customer_accounts layout="control" %}
                        {% bootstrap_field sform.customer_accounts_native layout="control" %}
+                        {% bootstrap_field sform.customer_accounts_require_login_for_order_access layout="control" %}
                        {% bootstrap_field sform.customer_accounts_link_by_email layout="control" %}
                        {% bootstrap_field sform.name_scheme layout="control" %}
                        {% bootstrap_field sform.name_scheme_titles layout="control" %}
@@ -22,7 +22,7 @@
                                {{ s.owner.fullname|default:s.owner.email }}
                            </span>
                        </div>
-                        <div class="col-lg-5 col-md-6 col-xs-12">
+                        <div class="col-lg-4 col-md-5 col-xs-12">
                            {% if s.schedule_next_run %}
                                <span class="fa fa-clock-o fa-fw"></span>
                                {% trans "Next run:" %}
@@ -53,7 +53,7 @@
                                {{ s.mail_subject }}
                            </span>
                        </div>
-                        <div class="col-lg-2 col-md-2 col-xs-12 text-right">
+                        <div class="col-lg-3 col-md-3 col-xs-12 text-right">
                            <form action="{% url "control:organizer.export.do" organizer=request.organizer.slug %}"
                                  method="post" class="form-horizontal" data-asynctask data-asynctask-download
                                  data-asynctask-long>
@@ -73,6 +73,9 @@
                                    <a href="?identifier={{ s.export_identifier }}&scheduled={{ s.pk }}" class="btn btn-default" title="{% trans "Edit" %}" data-toggle="tooltip">
                                        <span class="fa fa-edit"></span>
                                    </a>
+                                    <a href="?identifier={{ s.export_identifier }}&scheduled_copy_from={{ s.pk }}" class="btn btn-default" title="{% trans "Copy" %}" data-toggle="tooltip">
+                                        <span class="fa fa-copy"></span>
+                                    </a>
                                {% endif %}
                                <a href="{% url "control:organizer.export.scheduled.delete" organizer=request.organizer.slug pk=s.pk %}" class="btn btn-danger" title="{% trans "Delete" %}" data-toggle="tooltip">
                                    <span class="fa fa-trash"></span>
@@ -43,7 +43,11 @@
            <div class="form-group submit-group">
                <button formaction="{{ request.get_full_path }}" name="schedule" value="save" type="submit"
                        class="btn btn-primary btn-save" data-no-asynctask>
-                    {% trans "Save" %}
+                    {% if scheduled_copy_from %}
+                        {% trans "Save copy" %}
+                    {% else %}
+                        {% trans "Save" %}
+                    {% endif %}
                </button>
            </div>
        {% else %}
@@ -65,6 +65,9 @@

                    {% blocktrans asvar title_reset %}Customer account password reset{% endblocktrans %}
                    {% include "pretixcontrol/event/mail_settings_fragment.html" with pid="reset" title=title_reset items="mail_subject_customer_reset,mail_text_customer_reset" %}
+
+                    {% blocktrans asvar title_security_notice %}Customer account security notification{% endblocktrans %}
+                    {% include "pretixcontrol/event/mail_settings_fragment.html" with pid="security_notice" title=title_security_notice items="mail_subject_customer_security_notice,mail_text_customer_security_notice" %}
                </div>
            </fieldset>
        </div>
@@ -0,0 +1,222 @@
+{% extends "pretixcontrol/organizers/base.html" %}
+{% load i18n %}
+{% load bootstrap3 %}
+{% load urlreplace %}
+{% load icon %}
+{% load compress %}
+{% load static %}
+{% block inner %}
+    <h1>
+        {% trans "Outgoing email" %}
+    </h1>
+    <div class="panel panel-default">
+        <div class="panel-heading">
+            <h3 class="panel-title">{% trans "Email details" %}</h3>
+        </div>
+        <div class="panel-body">
+            <div class="row">
+                <div class="col-lg-7 col-md-12">
+
+                    <dl class="dl-horizontal">
+                        <dt>{% trans "From" context "email" %}</dt>
+                        <dd>{{ sender }}</dd>
+                        <dt>{% trans "To" context "email" %}</dt>
+                        <dd>{{ mail.to|join:", " }}</dd>
+                        {% if mail.cc %}
+                            <dt>{% trans "Cc" context "email" %}</dt>
+                            <dd>{{ mail.cc|join:", " }}</dd>
+                        {% endif %}
+                        {% if mail.bcc %}
+                            <dt>{% trans "Bcc" context "email" %}</dt>
+                            <dd>{{ mail.bcc|join:", " }}</dd>
+                        {% endif %}
+                        <dt>{% trans "Subject" %}</dt>
+                        <dd>{{ mail.subject }}</dd>
+                        <dt>{% trans "Status" %}</dt>
+                        <dd>
+                            {% if mail.status == "queued" %}
+                                <span class="label label-info">{% icon "clock-o" %} {% trans "queued" %}</span>
+                            {% elif mail.status == "inflight" %}
+                                <span class="label label-info">{% icon "send" %} {% trans "being sent" %}</span>
+                            {% elif mail.status == "awaiting_retry" %}
+                                <span class="label label-warning">{% icon "repeat" %} {% trans "will be retried" %}</span>
+                            {% elif mail.status == "failed" %}
+                                <span class="label label-danger">{% icon "warning" %} {% trans "failed" %}</span>
+                            {% elif mail.status == "bounced" %}
+                                <span class="label label-danger">{% icon "exclamation-circle" %} {% trans "bounced" %}</span>
+                            {% elif mail.status == "withheld" %}
+                                <span class="label label-warning">{% icon "ban" %} {% trans "withheld" %}</span>
+                            {% elif mail.status == "aborted" %}
+                                <span class="label label-danger">{% icon "ban" %} {% trans "aborted" %}</span>
+                            {% elif mail.status == "sent" %}
+                                <span class="label label-success">{% icon "check" %} {% trans "sent" %}</span>
+                            {% endif %}
+                        </dd>
+                        <dt>{% trans "Creation" %}</dt>
+                        <dd>{{ mail.created|date:"SHORT_DATETIME_FORMAT" }}</dd>
+                        {% if mail.sent %}
+                            <dt>{% trans "Sent" %}</dt>
+                            <dd>{{ mail.sent|date:"SHORT_DATETIME_FORMAT" }}</dd>
+                        {% endif %}
+                        {% if mail.retry_after and mail.status == "awaiting_retry" %}
+                            <dt>{% trans "Next attempt (estimate)" %}</dt>
+                            <dd>{{ mail.retry_after|date:"SHORT_DATETIME_FORMAT" }}</dd>
+                        {% endif %}
+                        {% if mail.event %}
+                            <dt>{% trans "Event" %}</dt>
+                            <dd>
+                                <a href="{% url "control:event.index" organizer=request.organizer.slug event=mail.event.slug %}">
+                                    {{ mail.event }}
+                                </a>
+                            </dd>
+                        {% endif %}
+                        {% if mail.order %}
+                            <dt>{% trans "Order" %}</dt>
+                            <dd>
+                                <a href="{% url "control:event.order" organizer=request.organizer.slug event=mail.event.slug code=mail.order.code %}">
+                                    {{ mail.order.code }}</a>{% if mail.orderposition %}-
+                                {{ mail.orderposition.positionid }}{% endif %}
+                            </dd>
+                        {% endif %}
+                        {% if mail.customer %}
+                            <dt>{% trans "Customer" %}</dt>
+                            <dd>
+                                {% icon "user fa-fw" %}
+                                <a href="{% url "control:organizer.customer" organizer=request.organizer.slug customer=mail.customer.identifier %}">
+                                    {{ mail.customer }}
+                                </a>
+                            </dd>
+                        {% endif %}
+                    </dl>
+                </div>
+                {% if mail.actual_attachments %}
+                    <div class="col-lg-5 col-md-12">
+                        <strong>{% trans "Attachments" %}</strong><br>
+                        <ul class="list-unstyled">
+                            {% for a in mail.actual_attachments %}
+                                <li>
+                                    {% if a.type == "text/calendar" %}
+                                        {% icon "calendar-plus-o fa-fw" %}
+                                    {% elif a.type == "application/pdf" %}
+                                        {% icon "file-pdf-o fa-fw" %}
+                                    {% elif "image/" in a.type %}
+                                        {% icon "file-image-o fa-fw" %}
+                                    {% elif "msword" in a.type or "document" in a.type %}
+                                        {% icon "file-word-o fa-fw" %}
+                                    {% elif "excel" in a.type or "spreadsheet" in a.type %}
+                                        {% icon "file-excel-o fa-fw" %}
+                                    {% elif "powerpoint" in a.type or "presentation" in a.type %}
+                                        {% icon "file-powerpoint-o fa-fw" %}
+                                    {% elif "pkpass" in a.type %}
+                                        {% icon "qrcode fa-fw" %}
+                                    {% else %}
+                                        {% icon "file-o fa-fw" %}
+                                    {% endif %}
+                                    {{ a.name }}
+                                    <span class="text-muted">
+                                        ({{ a.size|filesizeformat }})
+                                    </span>
+                                </li>
+                            {% endfor %}
+                        </ul>
+                    </div>
+                {% endif %}
+            </div>
+        </div>
+    </div>
+    <div>
+        <ul class="nav nav-tabs" role="tablist">
+            {% if mail.is_failed %}
+                <li role="presentation" class="active">
+                    <a href="#tab-error" role="tab" data-toggle="tab">
+                        <span class="fa fa-warning"></span>
+                        {% trans "Error" %}
+                    </a>
+                </li>
+            {% endif %}
+            {% if mail.body_html %}
+                <li role="presentation"
+                    {% if not mail.is_failed %}class="active"{% endif %}>
+                    <a href="#tab-html" role="tab" data-toggle="tab">
+                        <span class="fa fa-eye"></span>
+                        {% trans "HTML content" %}
+                    </a>
+                </li>
+            {% endif %}
+            <li role="presentation"
+                {% if not mail.is_failed and not mail.body_html %}class="active"{% endif %}>
+                <a href="#tab-text" role="tab" data-toggle="tab">
+                    <span class="fa fa-file-text-o"></span>
+                    {% trans "Text content" %}
+                </a>
+            </li>
+            <li role="presentation">
+                <a href="#tab-headers" role="tab" data-toggle="tab">
+                    <span class="fa fa-code"></span>
+                    {% trans "Headers" %}
+                </a>
+            </li>
+        </ul>
+
+        <div class="tab-content">
+            {% if mail.is_failed %}
+                <div role="tabpanel" class="tab-pane active" id="tab-error">
+                    <strong>
+                        {{ mail.error }}
+                    </strong>
+                    <pre>{{ mail.error_detail }}</pre>
+                </div>
+            {% endif %}
+            {% if mail.body_html %}
+                <div role="tabpanel"
+                     class="tab-pane {% if not mail.is_failed %}active{% endif %}"
+                     id="tab-html">
+                    {% if mail.sensitive %}
+                        <div class="empty-collection">
+                            <p>
+                                {% icon "eye-slash fa-4x" %}
+                            </p>
+                            <p>
+                                {% blocktrans trimmed %}
+                                    Sensitive content not shown for security reasons
+                                {% endblocktrans %}
+                            </p>
+                        </div>
+                    {% else %}
+                        {{ data_url|json_script:"mail_body_html" }}
+                    {% endif %}
+                </div>
+            {% endif %}
+            <div role="tabpanel"
+                 class="tab-pane {% if not mail.is_failed and not mail.body_html %}active{% endif %}"
+                 id="tab-text">
+                {% if mail.sensitive %}
+                    <div class="empty-collection">
+                        <p>
+                            {% icon "eye-slash fa-4x" %}
+                        </p>
+                        <p>
+                            {% blocktrans trimmed %}
+                                Sensitive content not shown for security reasons
+                            {% endblocktrans %}
+                        </p>
+                    </div>
+                {% else %}
+                    <pre><code>{{ mail.body_plain }}</code></pre>
+                {% endif %}
+            </div>
+            <div role="tabpanel"
+                 class="tab-pane"
+                 id="tab-headers">
+                <pre><code>{% for k, v in mail.headers.items %}{{ k }}: {{ v }}<br>{% endfor %}</code></pre>
+                <p class="text-muted">
+                    {% trans "Additional headers will be added by the mail server and are not visible here." %}
+                </p>
+            </div>
+        </div>
+
+    </div>
+    {% compress js %}
+        <script type="text/javascript" src="{% static "pretixcontrol/js/ui/outgoingmail.js" %}"></script>
+    {% endcompress %}
+{% endblock %}
@@ -0,0 +1,185 @@
+{% extends "pretixcontrol/organizers/base.html" %}
+{% load i18n %}
+{% load bootstrap3 %}
+{% load urlreplace %}
+{% load icon %}
+{% block inner %}
+    <h1>
+        {% trans "Outgoing emails" %}
+    </h1>
+    <p>
+        {% blocktrans trimmed with days=days %}
+            This is an overview of all emails sent by your organizer account in the last {{ days }} days.
+        {% endblocktrans %}
+    </p>
+    {% if mails|length == 0 and not filter_form.filtered %}
+        <div class="empty-collection">
+            <p>
+                {% blocktrans trimmed %}
+                    You haven't sent any emails recently.
+                {% endblocktrans %}
+            </p>
+        </div>
+    {% else %}
+        <div class="panel panel-default">
+            <div class="panel-heading">
+                <h3 class="panel-title">{% trans "Filter" %}</h3>
+            </div>
+            <form class="panel-body filter-form" action="" method="get">
+                <div class="row">
+                    <div class="col-md-4 col-sm-6 col-xs-12">
+                        {% bootstrap_field filter_form.query %}
+                    </div>
+                    <div class="col-md-3 col-sm-6 col-xs-12">
+                        {% bootstrap_field filter_form.status %}
+                    </div>
+                    <div class="col-md-5 col-sm-6 col-xs-12">
+                        {% bootstrap_field filter_form.event %}
+                    </div>
+                </div>
+                <div class="text-right">
+                    <button class="btn btn-primary btn-lg" type="submit">
+                        <span class="fa fa-filter"></span>
+                        {% trans "Filter" %}
+                    </button>
+                </div>
+            </form>
+        </div>
+        <form action="{% url "control:organizer.outgoingmails.bulk_action" organizer=request.organizer.slug %}" method="post">
+            {% csrf_token %}
+            {% for field in filter_form %}
+                {{ field.as_hidden }}
+            {% endfor %}
+            <div class="table-responsive">
+                <table class="table table-condensed table-hover table-quotas">
+                    <thead>
+                    <tr>
+                        <th>
+                            <label aria-label="{% trans "select all rows for batch-operation" %}"
+                                   class="batch-select-label"><input type="checkbox" data-toggle-table/></label>
+                        </th>
+                        <th>{% trans "Subject" %}</th>
+                        <th>{% trans "Recipients" %}</th>
+                        <th>{% trans "Context" %}</th>
+                        <th>{% trans "Status" %}</th>
+                        <th>{% trans "Date" %}
+                            <a href="?{% url_replace request 'ordering' '-date' %}"><i
+                                    class="fa fa-caret-down"></i></a>
+                            <a href="?{% url_replace request 'ordering' 'date' %}"><i class="fa fa-caret-up"></i></a>
+                        </th>
+                        <th></th>
+                    </tr>
+                    {% if page_obj.paginator.num_pages > 1 %}
+                        <tr class="table-select-all warning hidden">
+                            <td>
+                                <input type="checkbox" name="__ALL" id="__all"
+                                       data-results-total="{{ page_obj.paginator.count }}">
+                            </td>
+                            <td colspan="7">
+                                <label for="__all">
+                                    {% trans "Select all results on other pages as well" %}
+                                </label>
+                            </td>
+                        </tr>
+                    {% endif %}
+                    </thead>
+                    <tbody>
+                    {% for m in mails %}
+                        <tr>
+                            <td>
+                                <label aria-label="{% trans "select row for batch-operation" %}"
+                                       class="batch-select-label"><input type="checkbox" name="outgoingmail"
+                                                                         class="batch-select-checkbox"
+                                                                         value="{{ m.pk }}"/></label>
+                            </td>
+                            <td>
+                                <a href="{% url "control:organizer.outgoingmail" organizer=request.organizer.slug mail=m.id %}">
+                                    {{ m.subject }}
+                                </a>
+                                {% if m.sensitive %}
+                                    <span class="text-muted">{% icon "eye-slash" %}</span>
+                                {% endif %}
+                            </td>
+                            <td>
+                                {{ m.to|join:", " }}
+                                {% if m.cc %}
+                                    <br><small class="text-muted">{% trans "Cc" context "email" %}: {{ m.cc|join:", " }}</small>
+                                {% endif %}
+                                {% if m.bcc %}
+                                    <br><small class="text-muted">{% trans "Bcc" context "email" %}: {{ m.bcc|join:", " }}</small>
+                                {% endif %}
+                            </td>
+                            <td>
+                                {% if m.event %}
+                                    <div>
+                                        {% icon "calendar fa-fw" %}
+                                        <a href="{% url "control:event.index" organizer=request.organizer.slug event=m.event.slug %}">
+                                            {{ m.event }}
+                                        </a>
+                                    </div>
+                                {% endif %}
+                                {% if m.order %}
+                                    <div>
+                                        {% icon "shopping-cart fa-fw" %}
+                                        <a href="{% url "control:event.order" organizer=request.organizer.slug event=m.event.slug code=m.order.code %}">
+                                            {{ m.order.code }}</a>{% if m.orderposition %}-{{ m.orderposition.positionid }}{% endif %}
+                                    </div>
+                                {% endif %}
+                                {% if m.customer %}
+                                    <div>
+                                        {% icon "user fa-fw" %}
+                                        <a href="{% url "control:organizer.customer" organizer=request.organizer.slug customer=m.customer.identifier %}">
+                                            {{ m.customer }}
+                                        </a>
+                                    </div>
+                                {% endif %}
+                            </td>
+                            <td>
+                                {% if m.status == "queued" %}
+                                    <span class="label label-info">{% icon "clock-o" %} {% trans "queued" %}</span>
+                                {% elif m.status == "inflight" %}
+                                    <span class="label label-info">{% icon "send" %} {% trans "being sent" %}</span>
+                                {% elif m.status == "awaiting_retry" %}
+                                    <span class="label label-warning">{% icon "repeat" %} {% trans "will be retried" %}</span>
+                                {% elif m.status == "failed" %}
+                                    <span class="label label-danger">{% icon "warning" %} {% trans "failed" %}</span>
+                                {% elif m.status == "bounced" %}
+                                    <span class="label label-danger">{% icon "exclamation-circle" %} {% trans "bounced" %}</span>
+                                {% elif m.status == "withheld" %}
+                                    <span class="label label-warning">{% icon "ban" %} {% trans "withheld" %}</span>
+                                {% elif m.status == "aborted" %}
+                                    <span class="label label-danger">{% icon "ban" %} {% trans "aborted" %}</span>
+                                {% elif m.status == "sent" %}
+                                    <span class="label label-success">{% icon "check" %} {% trans "sent" %}</span>
+                                {% endif %}
+                            </td>
+                            <td>
+                                {{ m.created|date:"SHORT_DATETIME_FORMAT" }}
+                                {% if m.sent %}
+                                    <br>
+                                    <small class="text-muted">{% trans "Sent:" %} {{ m.sent|date:"SHORT_DATETIME_FORMAT" }}</small>
+                                {% endif %}
+                            </td>
+                            <td class="text-right flip">
+                                <a href="{% url "control:organizer.outgoingmail" organizer=request.organizer.slug mail=m.id %}"
+                                   class="btn btn-default btn-sm">{% icon "eye" %}</a>
+                            </td>
+                        </tr>
+                    {% endfor %}
+                    </tbody>
+                </table>
+            </div>
+            <div class="batch-select-actions">
+                <button type="submit" class="btn btn-primary btn-save" name="action" value="retry">
+                    {% icon "repeat" %}
+                    {% trans "Retry (if failed or withheld)" %}
+                </button>
+                <button type="submit" class="btn btn-danger btn-save" name="action" value="abort">
+                    {% icon "ban" %}
+                    {% trans "Abort (if queued, awaiting retry or withheld)" %}
+                </button>
+            </div>
+        </form>
+        {% include "pretixcontrol/pagination.html" %}
+    {% endif %}
+{% endblock %}
@@ -165,7 +165,7 @@
                                {% if v.budget|default_if_none:"NONE" != "NONE" %}
                                    <br>
                                    <small class="text-muted">
-                                        {{ v.budget_used_orders|money:request.event.currency }} / {{ v.budget|money:request.event.currency }}
+                                        {{ v.budget_used|money:request.event.currency }} / {{ v.budget|money:request.event.currency }}
                                    </small>
                                {% endif %}
                            </td>
--- a/Show More
+++ b/Show More