Fatal error: Uncaught Error: Interface "Ratchet\Session\Serialize\HandlerInterface" not found in /users/danielstruebig/www/Dart_software/ratchet/Ratchet-master/src/Ratchet/Session/Serialize/PhpBinaryHandler.php:4 Stack trace: #0 {main} thrown in /users/danielstruebig/www/Dart_software/ratchet/Ratchet-master/src/Ratchet/Session/Serialize/PhpBinaryHandler.php on line 4