diff --git a/core/lib/Drupal.php b/core/lib/Drupal.php
index a4bd4962e19..28824bf8def 100644
--- a/core/lib/Drupal.php
+++ b/core/lib/Drupal.php
@@ -82,7 +82,7 @@ class Drupal {
   /**
    * The current system version.
    */
-  const VERSION = '8.9.20-dev';
+  const VERSION = '8.9.21-dev';
 
   /**
    * Core API compatibility.