.. include:: /Includes.rst.txt

==========================
TYPO3 Exception 1679051921
==========================

.. include:: /If-you-encounter-this-exception.rst.txt

LogicException (TYPO3 v12.4)
==================================

``Either $defaultControllerClassName or $defaultControllerAlias are unexpectedly null``

When upgrading from TYPO3 v10.4

Solution
--------

Use controller classes when registering plugins/modules:

https://docs.typo3.org/c/typo3/cms-core/main/en-us/Changelog/10.0/Deprecation-87550-UseControllerClassesWhenRegisteringPluginsmodules.html