diff --git a/pkgs/development/ocaml-modules/mimic/default.nix b/pkgs/development/ocaml-modules/mimic/default.nix
index 25169c7c4913..097ecb313534 100644
--- a/pkgs/development/ocaml-modules/mimic/default.nix
+++ b/pkgs/development/ocaml-modules/mimic/default.nix
@@ -8,6 +8,7 @@ buildDunePackage rec {
   version = "0.0.6";
 
   minimalOCamlVersion = "4.08";
+  duneVersion = "3";
 
   src = fetchurl {
     url = "https://github.com/dinosaure/mimic/releases/download/${version}/mimic-${version}.tbz";
diff --git a/pkgs/development/ocaml-modules/mimic/happy-eyeballs.nix b/pkgs/development/ocaml-modules/mimic/happy-eyeballs.nix
index 72e3f99ddbe7..193509dd4903 100644
--- a/pkgs/development/ocaml-modules/mimic/happy-eyeballs.nix
+++ b/pkgs/development/ocaml-modules/mimic/happy-eyeballs.nix
@@ -6,6 +6,7 @@ buildDunePackage {
   inherit (mimic) src version;
 
   minimalOCamlVersion = "4.08";
+  duneVersion = "3";
 
   strictDeps = true;