Fatal error: Uncaught Error: Interface "Drupal\Core\Entity\EntityDisplayModeInterface" not found in /home/www/drupal8/test/core/lib/Drupal/Core/Entity/EntityFormModeInterface.php:8 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Core/Entity/EntityFormModeInterface.php on line 8