Fatal error: Uncaught Error: Interface "Sabre\Xml\XmlSerializable" not found in /var/www/illumine/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedMethodSet.php:23 Stack trace: #0 {main} thrown in /var/www/illumine/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedMethodSet.php on line 23