diff --git a/pkgs/development/ocaml-modules/ocaml-monadic/default.nix b/pkgs/development/ocaml-modules/ocaml-monadic/default.nix
index 9a6dd1f7cb66..7201311a5335 100644
--- a/pkgs/development/ocaml-modules/ocaml-monadic/default.nix
+++ b/pkgs/development/ocaml-modules/ocaml-monadic/default.nix
@@ -6,7 +6,7 @@ buildDunePackage rec {
   pname = "ocaml-monadic";
   version = "0.5.0";
 
-  useDune2 = true;
+  duneVersion = "3";
 
   src = fetchFromGitHub {
     owner = "zepalmer";