diff --git a/pkgs/development/ocaml-modules/irmin/chunk.nix b/pkgs/development/ocaml-modules/irmin/chunk.nix
index 59bd81544945..61a0d6021ab6 100644
--- a/pkgs/development/ocaml-modules/irmin/chunk.nix
+++ b/pkgs/development/ocaml-modules/irmin/chunk.nix
@@ -4,6 +4,7 @@ buildDunePackage rec {
 
   pname = "irmin-chunk";
   inherit (irmin) version src strictDeps;
+  duneVersion = "3";
 
   propagatedBuildInputs = [ irmin fmt logs lwt ];
 
diff --git a/pkgs/development/ocaml-modules/irmin/containers.nix b/pkgs/development/ocaml-modules/irmin/containers.nix
index 73cd25f3170d..aa003f39b3f4 100644
--- a/pkgs/development/ocaml-modules/irmin/containers.nix
+++ b/pkgs/development/ocaml-modules/irmin/containers.nix
@@ -7,6 +7,7 @@ buildDunePackage {
   pname = "irmin-containers";
 
   inherit (ppx_irmin) src version strictDeps;
+  duneVersion = "3";
 
   nativeBuildInputs = [
     ppx_irmin
diff --git a/pkgs/development/ocaml-modules/irmin/default.nix b/pkgs/development/ocaml-modules/irmin/default.nix
index 66b572f576d6..485547ddcad6 100644
--- a/pkgs/development/ocaml-modules/irmin/default.nix
+++ b/pkgs/development/ocaml-modules/irmin/default.nix
@@ -9,7 +9,8 @@ buildDunePackage {
 
   inherit (ppx_irmin) src version strictDeps;
 
-  minimalOCamlVersion = "4.08";
+  minimalOCamlVersion = "4.10";
+  duneVersion = "3";
 
   propagatedBuildInputs = [
     astring
diff --git a/pkgs/development/ocaml-modules/irmin/fs.nix b/pkgs/development/ocaml-modules/irmin/fs.nix
index 1788cf1eda23..4b8d7c4b97aa 100644
--- a/pkgs/development/ocaml-modules/irmin/fs.nix
+++ b/pkgs/development/ocaml-modules/irmin/fs.nix
@@ -7,6 +7,7 @@ buildDunePackage rec {
   pname = "irmin-fs";
 
   inherit (irmin) version src strictDeps;
+  duneVersion = "3";
 
   propagatedBuildInputs = [ irmin astring logs lwt ];
 
diff --git a/pkgs/development/ocaml-modules/irmin/mirage.nix b/pkgs/development/ocaml-modules/irmin/mirage.nix
index 9e4bd9330799..2d7d0a891249 100644
--- a/pkgs/development/ocaml-modules/irmin/mirage.nix
+++ b/pkgs/development/ocaml-modules/irmin/mirage.nix
@@ -4,6 +4,7 @@ buildDunePackage {
   pname = "irmin-mirage";
 
   inherit (irmin) version src strictDeps;
+  duneVersion = "3";
 
   propagatedBuildInputs = [
     irmin fmt ptime mirage-clock
diff --git a/pkgs/development/ocaml-modules/irmin/pack.nix b/pkgs/development/ocaml-modules/irmin/pack.nix
index a1a2974a4d74..8c0c7b2a3b00 100644
--- a/pkgs/development/ocaml-modules/irmin/pack.nix
+++ b/pkgs/development/ocaml-modules/irmin/pack.nix
@@ -1,10 +1,11 @@
 { lib, buildDunePackage
-, index, ppx_irmin, irmin, optint, fmt, logs, lwt, mtime, cmdliner
+, index, ppx_irmin, irmin, optint, fmt, logs, lwt, mtime, cmdliner, checkseum, rusage
 , alcotest, alcotest-lwt, astring, irmin-test
 }:
 
 buildDunePackage rec {
-  minimalOCamlVersion = "4.08";
+  minimalOCamlVersion = "4.10";
+  duneVersion = "3";
 
   pname = "irmin-pack";
 
@@ -12,7 +13,7 @@ buildDunePackage rec {
 
   nativeBuildInputs = [ ppx_irmin ];
 
-  propagatedBuildInputs = [ index irmin optint fmt logs lwt mtime cmdliner ];
+  propagatedBuildInputs = [ index irmin optint fmt logs lwt mtime cmdliner checkseum rusage ];
 
   checkInputs = [ astring alcotest alcotest-lwt irmin-test ];
 
diff --git a/pkgs/development/ocaml-modules/irmin/ppx.nix b/pkgs/development/ocaml-modules/irmin/ppx.nix
index 83cd5b1d7f5f..4ff7f4a8bdd8 100644
--- a/pkgs/development/ocaml-modules/irmin/ppx.nix
+++ b/pkgs/development/ocaml-modules/irmin/ppx.nix
@@ -2,14 +2,15 @@
 
 buildDunePackage rec {
   pname = "ppx_irmin";
-  version = "3.4.1";
+  version = "3.5.1";
 
   src = fetchurl {
     url = "https://github.com/mirage/irmin/releases/download/${version}/irmin-${version}.tbz";
-    sha256 = "sha256-kig2EWww7GgGijhpSgm7pSHPR+3Q5K5E4Ha5tJY9oYA=";
+    hash = "sha256-zXiKjT9KPdGNwWChU9SuyR6vaw+0GtQUZNJsecMEqY4=";
   };
 
   minimalOCamlVersion = "4.10";
+  duneVersion = "3";
 
   propagatedBuildInputs = [
     ppx_repr
diff --git a/pkgs/development/ocaml-modules/irmin/test.nix b/pkgs/development/ocaml-modules/irmin/test.nix
index 942200bf429a..4e2ccce71663 100644
--- a/pkgs/development/ocaml-modules/irmin/test.nix
+++ b/pkgs/development/ocaml-modules/irmin/test.nix
@@ -8,6 +8,7 @@ buildDunePackage {
   pname = "irmin-test";
 
   inherit (irmin) version src strictDeps;
+  duneVersion = "3";
 
   nativeBuildInputs = [ ppx_irmin ];
 
diff --git a/pkgs/development/ocaml-modules/irmin/tezos.nix b/pkgs/development/ocaml-modules/irmin/tezos.nix
index 82a89daec359..ddfc0d073205 100644
--- a/pkgs/development/ocaml-modules/irmin/tezos.nix
+++ b/pkgs/development/ocaml-modules/irmin/tezos.nix
@@ -7,6 +7,7 @@ buildDunePackage rec {
   pname = "irmin-tezos";
 
   inherit (irmin) version src strictDeps;
+  duneVersion = "3";
 
   propagatedBuildInputs = [
     irmin
diff --git a/pkgs/development/ocaml-modules/rusage/default.nix b/pkgs/development/ocaml-modules/rusage/default.nix
new file mode 100644
index 000000000000..891784ba6def
--- /dev/null
+++ b/pkgs/development/ocaml-modules/rusage/default.nix
@@ -0,0 +1,20 @@
+{ lib, fetchurl, buildDunePackage }:
+
+buildDunePackage rec {
+  pname = "rusage";
+  version = "1.0.0";
+
+  duneVersion = "3";
+
+  src = fetchurl {
+    url = "https://github.com/CraigFe/ocaml-rusage/releases/download/${version}/rusage-${version}.tbz";
+    hash = "sha256-OgYA2Fe1goqoaOS45Z6FBJNNYN/uq+KQoUwG8KSo6Fk=";
+  };
+
+  meta = {
+    description = "Bindings to the GETRUSAGE(2) syscall";
+    homepage = "https://github.com/CraigFe/ocaml-rusage";
+    license = lib.licenses.mit;
+    maintainers = [ lib.maintainers.vbgl ];
+  };
+}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 57759ae28eec..77580b9a32f0 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -1238,6 +1238,8 @@ let
 
     rock = callPackage ../development/ocaml-modules/rock { };
 
+    rusage = callPackage ../development/ocaml-modules/rusage { };
+
     samplerate = callPackage ../development/ocaml-modules/samplerate { };
 
     secp256k1 = callPackage ../development/ocaml-modules/secp256k1 {