Fatal error: Uncaught Error: Class 'Sabre\Xml\Element\KeyValue' not found in /var/www/typo3/vendor/sabre/vobject/lib/Parser/XML/Element/KeyValue.php:16 Stack trace: #0 {main} thrown in /var/www/typo3/vendor/sabre/vobject/lib/Parser/XML/Element/KeyValue.php on line 16