diff --git a/pkgs/development/ocaml-modules/telegraml/default.nix b/pkgs/development/ocaml-modules/telegraml/default.nix
index 9fed705ce3ee..1aca2da2974c 100644
--- a/pkgs/development/ocaml-modules/telegraml/default.nix
+++ b/pkgs/development/ocaml-modules/telegraml/default.nix
@@ -10,6 +10,7 @@
 buildDunePackage rec {
   pname = "telegraml";
   version = "unstable-2021-06-17";
+  duneVersion = "3";
 
   src = fetchFromGitHub {
     owner = "nv-vn";