Fatal error: Uncaught Error: Class 'Neos\Flow\Core\Migrations\AbstractMigration' not found in /var/www/vhosts/www.thomas-bartholomaeus.de/content/neoscms/Packages/Framework/Neos.Flow/Migrations/Code/Version20201207104500.php:23 Stack trace: #0 {main} thrown in /var/www/vhosts/www.thomas-bartholomaeus.de/content/neoscms/Packages/Framework/Neos.Flow/Migrations/Code/Version20201207104500.php on line 23