Breaking: #96899 - “displayWarningMessages” hook removed

See Issue #96899

Description

The hook $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_befunc.php']['displayWarningMessages'] has been removed in favor of a new PSR-14 Event \TYPO3\CMS\Backend\Controller\Event\ModifyGenericBackendMessagesEvent.

The hook was used to display messages in the About module.

Impact

Registered hooks are not executed anymore.

Affected Installations

TYPO3 installations with custom extensions using this hook, which is very unlikely. The extension scanner will report possible usages.

Migration

The hook is removed without deprecation in order to allow extensions to work with TYPO3 v11 (using the hook) and v12+ (using the new Event) when implementing the Event as well without any further deprecations.

Use the PSR-14 Event as a direct replacement.