Fatal error: Uncaught Error: Interface 'TYPO3\CMS\Core\SingletonInterface' not found in /home/.sites/884/site2951/web/test/luger/typo3conf/ext/gridelements/Classes/Backend/ItemsProcFuncs/AbstractItemsProcFunc.php:35
Stack trace:
#0 {main}
  thrown in /home/.sites/884/site2951/web/test/luger/typo3conf/ext/gridelements/Classes/Backend/ItemsProcFuncs/AbstractItemsProcFunc.php on line 35