Fatal error: Uncaught Error: Interface "Psr\EventDispatcher\StoppableEventInterface" not found in /var/www/html/dev.hallescherfc.de/packages/hfcmembership/Classes/Event/MembershipStatusChangedEvent.php:8 Stack trace: #0 {main} thrown in /var/www/html/dev.hallescherfc.de/packages/hfcmembership/Classes/Event/MembershipStatusChangedEvent.php on line 8