diff --git a/lib/Alchemy/Phrasea/Core/Version.php b/lib/Alchemy/Phrasea/Core/Version.php
index 3a3ff63afc..5f488cdd5a 100644
--- a/lib/Alchemy/Phrasea/Core/Version.php
+++ b/lib/Alchemy/Phrasea/Core/Version.php
@@ -16,7 +16,7 @@ class Version
     /**
      * @var string
      */
-    private $number = '4.1.0-alpha.21a';
+    private $number = '4.1.0-alpha.20a';
 
     /**
      * @var string
diff --git a/lib/classes/patch/410alpha21a.php b/lib/classes/patch/410alpha20a.php
similarity index 96%
rename from lib/classes/patch/410alpha21a.php
rename to lib/classes/patch/410alpha20a.php
index 58091e62f2..ff02a35c96 100644
--- a/lib/classes/patch/410alpha21a.php
+++ b/lib/classes/patch/410alpha20a.php
@@ -11,10 +11,10 @@
 
 use Alchemy\Phrasea\Application;
 
-class patch_410alpha21a implements patchInterface
+class patch_410alpha20a implements patchInterface
 {
     /** @var string */
-    private $release = '4.1.0-alpha.21a';
+    private $release = '4.1.0-alpha.20a';
 
     /** @var array */
     private $concern = [base::DATA_BOX];