diff --git a/pkgs/development/ocaml-modules/genspio/default.nix b/pkgs/development/ocaml-modules/genspio/default.nix
index 44742cba04a..14537c24c8b 100644
--- a/pkgs/development/ocaml-modules/genspio/default.nix
+++ b/pkgs/development/ocaml-modules/genspio/default.nix
@@ -6,6 +6,8 @@ buildDunePackage rec {
   pname = "genspio";
   version = "0.0.3";
 
+  duneVersion = "3";
+
   src = fetchFromGitHub {
     owner = "hammerlab";
     repo = pname;