diff --git a/src/pretix/__init__.py b/src/pretix/__init__.py
index cab334066..3d67cd6bb 100644
--- a/src/pretix/__init__.py
+++ b/src/pretix/__init__.py
@@ -1 +1 @@
-__version__ = "2.4.0.dev0"
+__version__ = "2.4.0"
diff --git a/src/setup.py b/src/setup.py
index 52f6de2f3..1359fb8f8 100644
--- a/src/setup.py
+++ b/src/setup.py
@@ -146,14 +146,15 @@ setup(
         'dev': [
             'django-debug-toolbar==1.9.1',
             'sqlparse==0.2.1',
-            'pycodestyle >= 2.4.0, < 2.5.0',
-            'pyflakes >= 2.0.0, < 2.1.0',
-            'flake8',
+            'pycodestyle==2.5.*',
+            'pyflakes==2.1.*',
+            'flake8==3.7.*',
             'pep8-naming',
             'coveralls',
             'coverage',
             'pytest==3.6.*',
             'pytest-django',
+            'pytest-xdist',
             'isort',
             'pytest-mock==1.6.*',
             'pytest-rerunfailures',