diff --git a/pkgs/development/ocaml-modules/qtest/default.nix b/pkgs/development/ocaml-modules/qtest/default.nix
index ea0237201dc1..982e1ed92472 100644
--- a/pkgs/development/ocaml-modules/qtest/default.nix
+++ b/pkgs/development/ocaml-modules/qtest/default.nix
@@ -4,8 +4,6 @@ buildDunePackage rec {
   pname = "qtest";
   version = "2.11.2";
 
-  duneVersion = "3";
-
   src = fetchFromGitHub {
     owner = "vincent-hugot";
     repo = pname;
@@ -13,6 +11,12 @@ buildDunePackage rec {
     sha256 = "sha256-VLY8+Nu6md0szW4RVxTFwlSQ9kyrgUqf7wQEA6GW8BE=";
   };
 
+  preBuild = ''
+    substituteInPlace src/dune \
+      --replace "(libraries bytes)" "" \
+      --replace "libraries qcheck ounit2 bytes" "libraries qcheck ounit2"
+  '';
+
   propagatedBuildInputs = [ qcheck ];
 
   meta = {