diff --git a/pkgs/development/ocaml-modules/stringext/default.nix b/pkgs/development/ocaml-modules/stringext/default.nix
index 3d440cf4895..32d801f971f 100644
--- a/pkgs/development/ocaml-modules/stringext/default.nix
+++ b/pkgs/development/ocaml-modules/stringext/default.nix
@@ -8,7 +8,7 @@ let version = "1.6.0"; in
 buildDunePackage {
   pname = "stringext";
   version = version;
-  useDune2 = true;
+  duneVersion = "3";
   src = fetchurl {
     url = "https://github.com/rgrinberg/stringext/releases/download/${version}/stringext-${version}.tbz";
     sha256 = "1sh6nafi3i9773j5mlwwz3kxfzdjzsfqj2qibxhigawy5vazahfv";