diff --git a/CHANGELOG b/CHANGELOG
index 660ff5df2..dec7b6626 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,7 @@
+* 2.12.4 (2020-XX-XX)
+
+ * n/a
+
 * 2.12.3 (2019-12-28)
 
  * fixed Symfony 5.0 support for the HTML extra extension
diff --git a/src/Environment.php b/src/Environment.php
index 420a72f5f..e0bc9a175 100644
--- a/src/Environment.php
+++ b/src/Environment.php
@@ -38,12 +38,12 @@ use Twig\TokenParser\TokenParserInterface;
  */
 class Environment
 {
-    const VERSION = '2.12.3';
-    const VERSION_ID = 21203;
+    const VERSION = '2.12.4-DEV';
+    const VERSION_ID = 21204;
     const MAJOR_VERSION = 2;
     const MINOR_VERSION = 12;
-    const RELEASE_VERSION = 3;
-    const EXTRA_VERSION = '';
+    const RELEASE_VERSION = 4;
+    const EXTRA_VERSION = 'DEV';
 
     private $charset;
     private $loader;