diff --git a/framework/BaseYii.php b/framework/BaseYii.php
index ca31a0601d..e706f531ed 100644
--- a/framework/BaseYii.php
+++ b/framework/BaseYii.php
@@ -93,7 +93,7 @@ class BaseYii
      */
     public static function getVersion()
     {
-        return '2.0.20';
+        return '2.0.21-dev';
     }
 
     /**
diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 624610024e..f097d3468d 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -1,6 +1,12 @@
 Yii Framework 2 Change Log
 ==========================
 
+2.0.21 under development
+------------------------
+
+- no changes in this release.
+
+
 2.0.20 June 04, 2019
 --------------------