diff --git a/pkgs/tools/networking/mu/default.nix b/pkgs/tools/networking/mu/default.nix
index db8f9bdb9d1a..4b9efdc24a60 100644
--- a/pkgs/tools/networking/mu/default.nix
+++ b/pkgs/tools/networking/mu/default.nix
@@ -7,13 +7,13 @@
 
 stdenv.mkDerivation rec {
   pname = "mu";
-  version = "1.6.5";
+  version = "1.6.6";
 
   src = fetchFromGitHub {
     owner  = "djcb";
     repo   = "mu";
     rev    = version;
-    sha256 = "ZHEUJiEJzQzSwWgY07dDflY5GRiD1We435htY/7IOdQ=";
+    sha256 = "64TfXPz1NCGKnozI9j+yog+hln1rA/qpzCLvPNSvH+c=";
   };
 
   postPatch = lib.optionalString (batchSize != null) ''