diff --git a/pkgs/by-name/x4/x42-gmsynth/package.nix b/pkgs/by-name/x4/x42-gmsynth/package.nix
index c7e77890c370..ffc7def4d9c7 100644
--- a/pkgs/by-name/x4/x42-gmsynth/package.nix
+++ b/pkgs/by-name/x4/x42-gmsynth/package.nix
@@ -9,13 +9,13 @@
 
 stdenv.mkDerivation (finalAttrs: {
   pname = "x42-gmsynth";
-  version = "0.6.3";
+  version = "0.6.4";
 
   src = fetchFromGitHub {
     owner = "x42";
     repo = "gmsynth.lv2";
     tag = "v${finalAttrs.version}";
-    hash = "sha256-js7c8d+yOjrRBs/xtHNfhXAcbiPX1PKFjHsThtEgzPQ=";
+    hash = "sha256-PDuvVNw9hxJVJwEYGeBJDKAt9ogHHJWELw/8LT+ZnVQ=";
   };
 
   nativeBuildInputs = [ pkg-config ];