Fatal error: Uncaught Error: Interface "Psr\EventDispatcher\StoppableEventInterface" not found in /var/www/html/dev.hallescherfc.de/vendor/typo3/cms-backend/Classes/View/Event/AbstractSectionMarkupGeneratedEvent.php:23 Stack trace: #0 {main} thrown in /var/www/html/dev.hallescherfc.de/vendor/typo3/cms-backend/Classes/View/Event/AbstractSectionMarkupGeneratedEvent.php on line 23