Fatal error: Uncaught Error: Class "Doctrine\ORM\Persisters\AbstractCollectionPersister" not found in /var/www/apache/dev/cal/web/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/ElementCollectionPersister.php:27 Stack trace: #0 {main} thrown in /var/www/apache/dev/cal/web/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/ElementCollectionPersister.php on line 27