diff --git a/pkgs/development/tools/ocaml/merlin/default.nix b/pkgs/development/tools/ocaml/merlin/default.nix
index 34fcc9bb6c3..ce168084f2c 100644
--- a/pkgs/development/tools/ocaml/merlin/default.nix
+++ b/pkgs/development/tools/ocaml/merlin/default.nix
@@ -4,7 +4,7 @@
 buildDunePackage rec {
   pname = "merlin";
 
-  inherit (dot-merlin-reader) src version;
+  inherit (dot-merlin-reader) src version useDune2;
 
   minimumOCamlVersion = "4.02.3";
 
diff --git a/pkgs/development/tools/ocaml/merlin/dot-merlin-reader.nix b/pkgs/development/tools/ocaml/merlin/dot-merlin-reader.nix
index 7af1b4513a8..009998a3f85 100644
--- a/pkgs/development/tools/ocaml/merlin/dot-merlin-reader.nix
+++ b/pkgs/development/tools/ocaml/merlin/dot-merlin-reader.nix
@@ -4,13 +4,15 @@ with ocamlPackages;
 
 buildDunePackage rec {
   pname = "dot-merlin-reader";
-  version = "3.4.0";
+  version = "3.4.2";
+
+  useDune2 = true;
 
   minimumOCamlVersion = "4.02.1";
 
   src = fetchurl {
     url = "https://github.com/ocaml/merlin/releases/download/v${version}/merlin-v${version}.tbz";
-    sha256 = "048rkpbvayksv8mgmkgi17vv0y9xplv7v2ww4d1hs7bkm5zzsvg2";
+    sha256 = "109ai1ggnkrwbzsl1wdalikvs1zx940m6n65jllxj68in6bvidz1";
   };
 
   buildInputs = [ yojson csexp result ];