Fatal error: Uncaught Error: Class "Symfony\Component\HttpKernel\EventListener\AbstractSessionListener" not found in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\http-kernel\EventListener\SessionListener.php:30 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\http-kernel\EventListener\SessionListener.php on line 30