diff --git a/pkgs/development/ocaml-modules/dune-rpc/default.nix b/pkgs/development/ocaml-modules/dune-rpc/default.nix
index 2814f4e8f5da..d5031728eda5 100644
--- a/pkgs/development/ocaml-modules/dune-rpc/default.nix
+++ b/pkgs/development/ocaml-modules/dune-rpc/default.nix
@@ -4,8 +4,8 @@
   dune_3,
   csexp,
   stdune,
+  ocamlc-loc,
   ordering,
-  pp,
   xdg,
   dyn,
 }:
@@ -21,8 +21,8 @@ buildDunePackage {
   propagatedBuildInputs = [
     csexp
     stdune
+    ocamlc-loc
     ordering
-    pp
     xdg
     dyn
   ];
diff --git a/pkgs/development/tools/ocaml/dune/3.nix b/pkgs/development/tools/ocaml/dune/3.nix
index 059beb6372c6..c4dfd1374338 100644
--- a/pkgs/development/tools/ocaml/dune/3.nix
+++ b/pkgs/development/tools/ocaml/dune/3.nix
@@ -14,11 +14,11 @@ else
 
   stdenv.mkDerivation rec {
     pname = "dune";
-    version = "3.19.1";
+    version = "3.20.1";
 
     src = fetchurl {
       url = "https://github.com/ocaml/dune/releases/download/${version}/dune-${version}.tbz";
-      hash = "sha256-oQOG+YDNqUF9FGVGa+1Q3SrvnJO50GoPf+7tsKFUEVg=";
+      hash = "sha256-8I6V3igo6JHWiQbkQwtRFwMihSB7W8aE/F1FZS6zDgo=";
     };
 
     nativeBuildInputs = [