diff --git a/pkgs/development/ocaml-modules/mrmime/default.nix b/pkgs/development/ocaml-modules/mrmime/default.nix
index c7fa461a364a..8148f5b99c88 100644
--- a/pkgs/development/ocaml-modules/mrmime/default.nix
+++ b/pkgs/development/ocaml-modules/mrmime/default.nix
@@ -24,12 +24,12 @@
   uutf,
 }:
 
-buildDunePackage rec {
+buildDunePackage (finalAttrs: {
   pname = "mrmime";
   version = "0.7.0";
 
   src = fetchurl {
-    url = "https://github.com/mirage/mrmime/releases/download/v${version}/mrmime-${version}.tbz";
+    url = "https://github.com/mirage/mrmime/releases/download/v${finalAttrs.version}/mrmime-${finalAttrs.version}.tbz";
     hash = "sha256-w23xtro9WgyLLwqdwfqLMN/ZDqwpvFcEvurbsqnsJLc=";
   };
 
@@ -68,4 +68,4 @@ buildDunePackage rec {
     maintainers = [ ];
     mainProgram = "mrmime.generate";
   };
-}
+})