Fatal error: Uncaught Error: Class "SMW\Serializers\SemanticDataSerializer" not found in /var/www/html/extensions/SemanticMediaWiki/src/Serializers/FlatSemanticDataSerializer.php:14 Stack trace: #0 {main} thrown in /var/www/html/extensions/SemanticMediaWiki/src/Serializers/FlatSemanticDataSerializer.php on line 14