diff --git a/CHANGELOG b/CHANGELOG
index 1c89d2453..acf246347 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,7 @@
+* 2.12.6 (2020-XX-XX)
+
+ * n/a
+
 * 2.12.5 (2020-02-11)
 
  * Add a check to ensure that iconv() is defined
diff --git a/src/Environment.php b/src/Environment.php
index d0419fb95..86b517586 100644
--- a/src/Environment.php
+++ b/src/Environment.php
@@ -38,12 +38,12 @@ use Twig\TokenParser\TokenParserInterface;
  */
 class Environment
 {
-    const VERSION = '2.12.5';
-    const VERSION_ID = 21205;
+    const VERSION = '2.12.6-DEV';
+    const VERSION_ID = 21206;
     const MAJOR_VERSION = 2;
     const MINOR_VERSION = 12;
-    const RELEASE_VERSION = 5;
-    const EXTRA_VERSION = '';
+    const RELEASE_VERSION = 6;
+    const EXTRA_VERSION = 'DEV';
 
     private $charset;
     private $loader;