Dears,

I just upgraded my Server from Ubuntu 22.04 to 24.04 and I get the following error when accessing the web page.

Django is 5.0.10 Postorius is 1.3.13

Any help is welcome.

Thank you and kind regards Torge

Internal Server Error:/mailman3/lists/

ImportError at/mailman3/lists/ Module "django.contrib.sessions.serializers" does not define a "PickleSerializer" attribute/class

Request Method: GET Request URL:https://lists.lsv-pinneberg.de/mailman3/lists/ Django Version: 5.0.10 Python Executable: /usr/bin/uwsgi-core Python Version: 3.12.3 Python Path: ['.', '', '/usr/lib/python312.zip', '/usr/lib/python3.12', '/usr/lib/python3.12/lib-dynload', '/opt/mailman/web/venv/lib/python3.12/site-packages'] Server time: Sun, 22 Dec 2024 11:05:00 +0100 Installed Applications: ('hyperkitty', 'postorius', 'django_mailman3', 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.sites', 'django.contrib.messages', 'django.contrib.staticfiles', 'rest_framework', 'django_gravatar', 'compressor', 'haystack', 'django_extensions', 'django_q', 'allauth', 'allauth.account', 'allauth.socialaccount') Installed Middleware: ('django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.middleware.locale.LocaleMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware', 'django.middleware.security.SecurityMiddleware', 'django_mailman3.middleware.TimezoneMiddleware', 'postorius.middleware.PostoriusMiddleware', 'allauth.account.middleware.AccountMiddleware')

Traceback (most recent call last): File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/utils/module_loading.py", line 30, in import_string return cached_import(module_path, class_name) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/utils/module_loading.py", line 16, in cached_import return getattr(module, class_name) ^^^^^^^^^^^^^^^^^^^^^^^^^^^

The above exception (module 'django.contrib.sessions.serializers' has no attribute 'PickleSerializer') was the direct cause of the following exception: File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/core/handlers/exception.py", line 55, in inner response = get_response(request) ^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/utils/deprecation.py", line 133, in __call__ response = self.process_request(request) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/contrib/sessions/middleware.py", line 20, in process_request request.session = self.SessionStore(session_key) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/contrib/sessions/backends/db.py", line 16, in __init__ super().__init__(session_key) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/contrib/sessions/backends/base.py", line 47, in __init__ self.serializer = import_string(settings.SESSION_SERIALIZER) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/web/venv/lib/python3.12/site-packages/django/utils/module_loading.py", line 32, in import_string raise ImportError( ^^^^^^^^^^

Exception Type: ImportError at/mailman3/lists/ Exception Value: Module "django.contrib.sessions.serializers" does not define a "PickleSerializer" attribute/class Raised during: postorius.views.list.list_index