diff --git a/pkgs/development/ocaml-modules/mirage-block-unix/default.nix b/pkgs/development/ocaml-modules/mirage-block-unix/default.nix
index 0d0851536b3..e32523c85eb 100644
--- a/pkgs/development/ocaml-modules/mirage-block-unix/default.nix
+++ b/pkgs/development/ocaml-modules/mirage-block-unix/default.nix
@@ -13,6 +13,7 @@ buildDunePackage rec {
   };
 
   minimalOCamlVersion = "4.08";
+  duneVersion = "3";
 
   propagatedBuildInputs = [ cstruct-lwt logs mirage-block rresult uri ];