Fatal error: Uncaught Error: Interface "Symfony\Component\Serializer\Encoder\EncoderInterface" not found in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\serializer\Encoder\JsonEncode.php:21 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\cms_upgrade\vendor\symfony\serializer\Encoder\JsonEncode.php on line 21