Breaking: #72476 - PHP Constant TYPO3_PROCEED_IF_NO_USER removed 

See forge#72476

Description 

The PHP constant TYPO3_PROCEED_IF_NO_USER has been removed.

Impact 

Any checks on this constant will result in a fatal PHP error.

Any definition in custom entry-scripts of extensions will have no effect anymore.

Affected Installations 

Installations with custom entry-points for the TYPO3 Backend.

Migration 

Use a custom RequestHandler, the Backend Routing, AJAX Registration or the Module Configuration for skipping the user authentication when necessary.