diff --git a/eZ/Publish/API/Repository/Values/ObjectState/ObjectStateGroup.php b/eZ/Publish/API/Repository/Values/ObjectState/ObjectStateGroup.php
index <HASH>..<HASH> 100644
--- a/eZ/Publish/API/Repository/Values/ObjectState/ObjectStateGroup.php
+++ b/eZ/Publish/API/Repository/Values/ObjectState/ObjectStateGroup.php
@@ -40,7 +40,7 @@ abstract class ObjectStateGroup extends ValueObject
      *
      * @var string
      */
-    public $defaultLanguageCode;
+    protected $defaultLanguageCode;
 
      /**
      * The available language codes for names an descriptions
Fixed: Only protected members in domain value objects.