Fatal error: Uncaught Error: Class "Symfony\Component\Config\Definition\Builder\VariableNodeDefinition" not found in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\config\Definition\Builder\ScalarNodeDefinition.php:21 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\config\Definition\Builder\ScalarNodeDefinition.php on line 21