diff --git a/backup/backup.class.php b/backup/backup.class.php
index a80f303255c..54fca21ce78 100644
--- a/backup/backup.class.php
+++ b/backup/backup.class.php
@@ -160,7 +160,7 @@ abstract class backup implements checksumable {
     /**
      * Usually same than major release zero version, mainly for informative/historic purposes.
      */
-    const RELEASE = '3.9';
+    const RELEASE = '4.0';
 
     /**
      * Cipher to be used in backup and restore operations.