diff --git a/pkgs/development/ocaml-modules/functoria/default.nix b/pkgs/development/ocaml-modules/functoria/default.nix
index cf364347fa44..346083ddadb3 100644
--- a/pkgs/development/ocaml-modules/functoria/default.nix
+++ b/pkgs/development/ocaml-modules/functoria/default.nix
@@ -4,13 +4,14 @@
 
 buildDunePackage rec {
   pname   = "functoria";
-  version = "4.2.0";
+  version = "4.3.4";
 
+  duneVersion = "3";
   minimalOCamlVersion = "4.08";
 
   src = fetchurl {
     url = "https://github.com/mirage/mirage/releases/download/v${version}/mirage-${version}.tbz";
-    sha256 = "sha256-rZ9y8+wbDjqjY1sx+TmSoR42hUKRMGpehCCR2cEgbv8=";
+    hash = "sha256-ZN8La2+N19wVo/vBUfIj17JU6FSp0jX7h2nDoIpR1XY=";
   };
 
   propagatedBuildInputs = [ cmdliner rresult astring fmt logs bos fpath emile uri ];
diff --git a/pkgs/development/ocaml-modules/mirage/default.nix b/pkgs/development/ocaml-modules/mirage/default.nix
index 410475b6b5c0..98d96cf146f0 100644
--- a/pkgs/development/ocaml-modules/mirage/default.nix
+++ b/pkgs/development/ocaml-modules/mirage/default.nix
@@ -8,6 +8,7 @@ buildDunePackage rec {
   inherit (mirage-runtime) version src;
 
   minimalOCamlVersion = "4.08";
+  duneVersion = "3";
 
   outputs = [ "out" "dev" ];