diff --git a/pkgs/tools/networking/mu/default.nix b/pkgs/tools/networking/mu/default.nix
index ad49c5e6c321..bd035e8f03cb 100644
--- a/pkgs/tools/networking/mu/default.nix
+++ b/pkgs/tools/networking/mu/default.nix
@@ -5,13 +5,13 @@
 
 stdenv.mkDerivation rec {
   pname = "mu";
-  version = "1.3.5";
+  version = "1.2";
 
   src = fetchFromGitHub {
     owner  = "djcb";
     repo   = "mu";
     rev    = version;
-    sha256 = "1g7rhgp405v7q9xx44k6jn3py4v73a9qjwhai6l459wdywdz1n3n";
+    sha256 = "0yhjlj0z23jw3cf2wfnl98y8q6gikvmhkb8vdm87bd7jw0bdnrfz";
   };
 
   # test-utils coredumps so don't run those