diff --git a/Block/Widget/Featured.php b/Block/Widget/Featured.php
index d54ee64b..4683f982 100644
--- a/Block/Widget/Featured.php
+++ b/Block/Widget/Featured.php
@@ -46,7 +46,7 @@ public function getTitle()
      */
     protected function getPostIdsConfigValue()
     {
-        return $this->getData('posts_ids');
+        return (string)$this->getData('posts_ids');
     }
 
     /**