Fatal error: Uncaught Error: Interface "Psr\EventDispatcher\StoppableEventInterface" not found in /var/www/html/dev.hallescherfc.de/packages/muthsevcontent/Classes/Event/YieldClientExtensionNameEvent.php:7 Stack trace: #0 {main} thrown in /var/www/html/dev.hallescherfc.de/packages/muthsevcontent/Classes/Event/YieldClientExtensionNameEvent.php on line 7