From ca0c0f4ae3cad3a82819cab8799cede6e7d1f85f Mon Sep 17 00:00:00 2001
From: Raphael Michel <mail@raphaelmichel.de>
Date: Fri, 20 Sep 2019 11:22:00 +0200
Subject: [PATCH] Revert to multipart/related

---
 src/pretix/base/services/mail.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/pretix/base/services/mail.py b/src/pretix/base/services/mail.py
index 9eba3ba4f8..528f341e6f 100644
--- a/src/pretix/base/services/mail.py
+++ b/src/pretix/base/services/mail.py
@@ -378,7 +378,7 @@ def replace_images_with_cid_paths(body_html):
 def attach_cid_images(msg, cid_images, verify_ssl=True):
     if cid_images and len(cid_images) > 0:
 
-        msg.mixed_subtype = 'related'
+        msg.mixed_subtype = 'mixed'
         for key, image in enumerate(cid_images):
             cid = 'image_%s' % key
             try: