diff --git a/pkgs/by-name/ma/mathmod/package.nix b/pkgs/by-name/ma/mathmod/package.nix
index 2eec8e24f29d..02af5659929b 100644
--- a/pkgs/by-name/ma/mathmod/package.nix
+++ b/pkgs/by-name/ma/mathmod/package.nix
@@ -7,19 +7,20 @@
 
 stdenv.mkDerivation (finalAttrs: {
   pname = "mathmod";
-  version = "12.1";
+  version = "13.0";
 
   src = fetchFromGitHub {
     owner = "parisolab";
     repo = "mathmod";
     tag = finalAttrs.version;
-    hash = "sha256-gDIYDXI9X24JAM1HP10EhJXkHZV2X8QngD5KPCUqdyI=";
+    hash = "sha256-+UR8Tk20StplyNqPDNxR0HfjAzAru4r+WtVsW81LR9c=";
   };
 
   patches = [ ./fix-paths.patch ];
 
   postPatch = ''
-    substituteInPlace MathMod.pro --subst-var out
+    substituteInPlace MathMod.pro \
+      --replace-fail "@out@" "$out"
   '';
 
   nativeBuildInputs = with libsForQt5; [