Fatal error: Uncaught Error: Interface "Sabre\Xml\XmlSerializable" not found in /var/www/illumine/vendor/sabre/dav/lib/CalDAV/Xml/Property/EmailAddressSet.php:20 Stack trace: #0 {main} thrown in /var/www/illumine/vendor/sabre/dav/lib/CalDAV/Xml/Property/EmailAddressSet.php on line 20