--- /dev/null
+<?php
+
+namespace Drupal\Core\Entity\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * Validation constraint for the entity changed timestamp.
+ *
+ * @Constraint(
+ * id = "EntityUntranslatableFields",
+ * label = @Translation("Entity untranslatable fields", context = "Validation"),
+ * type = {"entity"}
+ * )
+ */
+class EntityUntranslatableFieldsConstraint extends Constraint {
+
+ public $defaultRevisionMessage = 'Non-translatable fields can only be changed when updating the current revision.';
+ public $defaultTranslationMessage = 'Non-translatable fields can only be changed when updating the original language.';
+
+}