diff --git a/pkgs/development/ocaml-modules/vchan/default.nix b/pkgs/development/ocaml-modules/vchan/default.nix
index 872d11606ff..e727c866766 100644
--- a/pkgs/development/ocaml-modules/vchan/default.nix
+++ b/pkgs/development/ocaml-modules/vchan/default.nix
@@ -9,10 +9,11 @@ buildDunePackage rec {
   version = "6.0.1";
 
   minimalOCamlVersion = "4.08";
+  duneVersion = "3";
 
   src = fetchurl {
     url = "https://github.com/mirage/ocaml-vchan/releases/download/v${version}/vchan-${version}.tbz";
-    sha256 = "sha256-5E7dITMVirYoxUkp8ZamRAolyhA6avXGJNAioxeBuV0=";
+    hash = "sha256-5E7dITMVirYoxUkp8ZamRAolyhA6avXGJNAioxeBuV0=";
   };
 
   propagatedBuildInputs = [