Fatal error: Uncaught Error: Class "Symfony\Component\DependencyInjection\ParameterBag\FrozenParameterBag" not found in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\dependency-injection\ParameterBag\ContainerBag.php:19 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\dependency-injection\ParameterBag\ContainerBag.php on line 19