Fatal error: Uncaught Error: Interface "TYPO3\CMS\Backend\Toolbar\ToolbarItemInterface" not found in /var/www/html/dev.hallescherfc.de/vendor/konradmichalik/typo3-environment-indicator/Classes/Backend/ToolbarItems/TopbarItem.php:35 Stack trace: #0 {main} thrown in /var/www/html/dev.hallescherfc.de/vendor/konradmichalik/typo3-environment-indicator/Classes/Backend/ToolbarItems/TopbarItem.php on line 35