diff --git a/databox/api/config/validator/validation.yaml b/databox/api/config/validator/validation.yaml
index cd0f018e9..089db42f7 100644
--- a/databox/api/config/validator/validation.yaml
+++ b/databox/api/config/validator/validation.yaml
@@ -48,7 +48,6 @@ App\Entity\Core\Attribute:
 
 App\Entity\Core\AbstractBaseAttribute:
   constraints:
-    - App\Validator\UniqueAttributeConstraint: ~
     - App\Validator\ValidAttributeConstraint: ~
   properties:
     value:
diff --git a/databox/api/migrations/Version20230920160828.php b/databox/api/migrations/Version20230920160828.php
new file mode 100644
index 000000000..5405ed920
--- /dev/null
+++ b/databox/api/migrations/Version20230920160828.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Connection;
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20230920160828 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Migrate from "array" to "json" Doctrine type';
+    }
+
+    public function up(Schema $schema): void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE attribute_definition ALTER fallback TYPE JSON USING fallback::json');
+        $this->addSql('COMMENT ON COLUMN attribute_definition.fallback IS NULL');
+        $this->addSql('ALTER TABLE file ALTER alternate_urls TYPE JSON USING alternate_urls::json');
+        $this->addSql('COMMENT ON COLUMN file.alternate_urls IS NULL');
+
+        $connection = $this->connection;
+
+        foreach ([
+            ['attribute_definition', 'fallback'],
+            ['file', 'alternate_urls'],
+                 ] as $t)
+        {
+            [$table, $column] = $t;
+            $rows = $connection->fetchAllAssociative(sprintf('SELECT "id", "%s" FROM "%s"', $column, $table));
+
+            foreach ($rows as $row) {
+                $connection->executeStatement(sprintf('UPDATE "%s" SET "%s" = :encodedData WHERE id = :id', $table, $column), [
+                    'encodedData' => json_encode(unserialize($row[$column])),
+                    'id' => $row['id'],
+                ]);
+            }
+        }
+    }
+
+    public function down(Schema $schema): void
+    {
+        throw new \InvalidArgumentException('Cannot revert');
+    }
+}
diff --git a/databox/api/src/Validator/ValidAttributeConstraintValidator.php b/databox/api/src/Validator/ValidAttributeConstraintValidator.php
index a17cdcb37..f63847f56 100644
--- a/databox/api/src/Validator/ValidAttributeConstraintValidator.php
+++ b/databox/api/src/Validator/ValidAttributeConstraintValidator.php
@@ -5,7 +5,7 @@
 namespace App\Validator;
 
 use App\Attribute\AttributeTypeRegistry;
-use App\Entity\Core\Attribute;
+use App\Entity\Core\AbstractBaseAttribute;
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\ConstraintValidator;
 
@@ -16,7 +16,7 @@ public function __construct(private readonly AttributeTypeRegistry $typeRegistry
     }
 
     /**
-     * @param Attribute               $value
+     * @param AbstractBaseAttribute               $value
      * @param SameWorkspaceConstraint $constraint
      */
     public function validate($value, Constraint $constraint): void
diff --git a/lib/php/admin-bundle/Field/IdField.php b/lib/php/admin-bundle/Field/IdField.php
index 0a1441ac1..893f9a453 100644
--- a/lib/php/admin-bundle/Field/IdField.php
+++ b/lib/php/admin-bundle/Field/IdField.php
@@ -15,6 +15,7 @@ public static function new(string $propertyName = 'id', $label = null): BaseIdFi
         }
 
         return BaseIdField::new($propertyName, $label)
+            ->hideOnForm()
             ->setTemplatePath('@AlchemyAdmin/list/id.html.twig');
     }
 }