Fatal error: Uncaught Error: Interface "Symfony\Component\Serializer\Encoder\DecoderInterface" not found in /srv/disk1/2895578/www/whittonphotographicclub.org.uk/concrete/vendor/symfony/serializer/Encoder/ContextAwareDecoderInterface.php:19 Stack trace: #0 {main} thrown in /srv/disk1/2895578/www/whittonphotographicclub.org.uk/concrete/vendor/symfony/serializer/Encoder/ContextAwareDecoderInterface.php on line 19