Fatal error: Uncaught Error: Class "MediaWiki\Extension\Notifications\Mapper\AbstractMapper" not found in /var/www/html/orian-wiki/extensions/Echo/includes/Mapper/TargetPageMapper.php:10 Stack trace: #0 {main} thrown in /var/www/html/orian-wiki/extensions/Echo/includes/Mapper/TargetPageMapper.php on line 10