Fatal error: Uncaught Error: Class "MediaWiki\Extension\Notifications\Mapper\AbstractMapper" not found in /var/www/html/orian-wiki/extensions/Echo/includes/Mapper/NotificationMapper.php:20
Stack trace:
#0 {main}
thrown in /var/www/html/orian-wiki/extensions/Echo/includes/Mapper/NotificationMapper.php on line 20