Breaking: #82433 - Install Tool entry point removed

See Issue #82433

Description

The canonical entry point for accessing the install tool now is typo3/install.php. The previous entrypoint located in typo3/sysext/install/Start/Install.php has been removed. The deprecated entrypoint located under typo3/install/index.php still exists, but typo3/install.php is the new way to access the install tool, available since TYPO3 8 LTS.

Impact

Accessing typo3/sysext/install/Start/Install.php will trigger a Server-based "Page Not Found" error message.

Affected Installations

Every TYPO3 installation using the old entry point is affected.

Migration

Change bookmarks or scripts from the old entry point to the new one.