Fatal error: Uncaught Error: Class 'Symfony\Component\Serializer\Normalizer\AbstractNormalizer' not found in /home1/heyerarc/public_html/updates/concrete5-8.5.5_remote_updater/concrete/vendor/symfony/serializer/Normalizer/AbstractObjectNormalizer.php:30 Stack trace: #0 {main} thrown in /home1/heyerarc/public_html/updates/concrete5-8.5.5_remote_updater/concrete/vendor/symfony/serializer/Normalizer/AbstractObjectNormalizer.php on line 30