diff --git a/pkgs/development/ocaml-modules/irmin/chunk.nix b/pkgs/development/ocaml-modules/irmin/chunk.nix
index 61a0d6021ab6..59bd81544945 100644
--- a/pkgs/development/ocaml-modules/irmin/chunk.nix
+++ b/pkgs/development/ocaml-modules/irmin/chunk.nix
@@ -4,7 +4,6 @@ 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 aa003f39b3f4..73cd25f3170d 100644
--- a/pkgs/development/ocaml-modules/irmin/containers.nix
+++ b/pkgs/development/ocaml-modules/irmin/containers.nix
@@ -7,7 +7,6 @@ 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 485547ddcad6..d273d19553c1 100644
--- a/pkgs/development/ocaml-modules/irmin/default.nix
+++ b/pkgs/development/ocaml-modules/irmin/default.nix
@@ -10,7 +10,6 @@ buildDunePackage {
   inherit (ppx_irmin) src version strictDeps;
 
   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 4b8d7c4b97aa..1788cf1eda23 100644
--- a/pkgs/development/ocaml-modules/irmin/fs.nix
+++ b/pkgs/development/ocaml-modules/irmin/fs.nix
@@ -7,7 +7,6 @@ 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/git.nix b/pkgs/development/ocaml-modules/irmin/git.nix
index c48928159130..387fc60a0aa9 100644
--- a/pkgs/development/ocaml-modules/irmin/git.nix
+++ b/pkgs/development/ocaml-modules/irmin/git.nix
@@ -10,7 +10,6 @@ buildDunePackage {
   pname = "irmin-git";
 
   inherit (irmin) version src strictDeps;
-  duneVersion = "3";
 
   propagatedBuildInputs = [
     git
diff --git a/pkgs/development/ocaml-modules/irmin/graphql.nix b/pkgs/development/ocaml-modules/irmin/graphql.nix
index 005bf25eb2d9..1b5ecb51396f 100644
--- a/pkgs/development/ocaml-modules/irmin/graphql.nix
+++ b/pkgs/development/ocaml-modules/irmin/graphql.nix
@@ -7,7 +7,6 @@ buildDunePackage rec {
   pname = "irmin-graphql";
 
   inherit (irmin) version src;
-  duneVersion = "3";
 
   propagatedBuildInputs = [ cohttp-lwt cohttp-lwt-unix graphql-cohttp graphql-lwt irmin git-unix ];
 
diff --git a/pkgs/development/ocaml-modules/irmin/http.nix b/pkgs/development/ocaml-modules/irmin/http.nix
index 9a466928c64a..1b376425bdce 100644
--- a/pkgs/development/ocaml-modules/irmin/http.nix
+++ b/pkgs/development/ocaml-modules/irmin/http.nix
@@ -9,8 +9,6 @@ buildDunePackage rec {
   pname = "irmin-http";
 
   inherit (irmin) version src strictDeps;
-  duneVersion = "3";
-
 
   propagatedBuildInputs = [ astring cohttp-lwt cohttp-lwt-unix fmt jsonm logs lwt uri irmin webmachine ];
 
@@ -25,5 +23,3 @@ buildDunePackage rec {
   };
 
 }
-
-
diff --git a/pkgs/development/ocaml-modules/irmin/mirage-git.nix b/pkgs/development/ocaml-modules/irmin/mirage-git.nix
index 1491439f7656..09c1820d6094 100644
--- a/pkgs/development/ocaml-modules/irmin/mirage-git.nix
+++ b/pkgs/development/ocaml-modules/irmin/mirage-git.nix
@@ -7,7 +7,6 @@ buildDunePackage {
   pname = "irmin-mirage-git";
 
   inherit (irmin-mirage) version src strictDeps;
-  duneVersion = "3";
 
   propagatedBuildInputs = [
     irmin-mirage
diff --git a/pkgs/development/ocaml-modules/irmin/mirage-graphql.nix b/pkgs/development/ocaml-modules/irmin/mirage-graphql.nix
index 75d3c567a04d..bfbe45b39019 100644
--- a/pkgs/development/ocaml-modules/irmin/mirage-graphql.nix
+++ b/pkgs/development/ocaml-modules/irmin/mirage-graphql.nix
@@ -6,7 +6,6 @@ buildDunePackage {
   pname = "irmin-mirage-graphql";
 
   inherit (irmin-mirage) version src strictDeps;
-  duneVersion = "3";
 
   propagatedBuildInputs = [
     irmin-mirage
diff --git a/pkgs/development/ocaml-modules/irmin/mirage.nix b/pkgs/development/ocaml-modules/irmin/mirage.nix
index 2d7d0a891249..9e4bd9330799 100644
--- a/pkgs/development/ocaml-modules/irmin/mirage.nix
+++ b/pkgs/development/ocaml-modules/irmin/mirage.nix
@@ -4,7 +4,6 @@ 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 8c0c7b2a3b00..9afb40c20766 100644
--- a/pkgs/development/ocaml-modules/irmin/pack.nix
+++ b/pkgs/development/ocaml-modules/irmin/pack.nix
@@ -4,8 +4,7 @@
 }:
 
 buildDunePackage rec {
-  minimalOCamlVersion = "4.10";
-  duneVersion = "3";
+  minimalOCamlVersion = "4.12";
 
   pname = "irmin-pack";
 
diff --git a/pkgs/development/ocaml-modules/irmin/ppx.nix b/pkgs/development/ocaml-modules/irmin/ppx.nix
index 4ff7f4a8bdd8..78207bf009e8 100644
--- a/pkgs/development/ocaml-modules/irmin/ppx.nix
+++ b/pkgs/development/ocaml-modules/irmin/ppx.nix
@@ -2,15 +2,14 @@
 
 buildDunePackage rec {
   pname = "ppx_irmin";
-  version = "3.5.1";
+  version = "3.7.2";
 
   src = fetchurl {
     url = "https://github.com/mirage/irmin/releases/download/${version}/irmin-${version}.tbz";
-    hash = "sha256-zXiKjT9KPdGNwWChU9SuyR6vaw+0GtQUZNJsecMEqY4=";
+    hash = "sha256-aqW6TGoCM3R9S9OrOW8rOjO7gPnY7UoXjIOgNQM8DlI=";
   };
 
   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 4e2ccce71663..942200bf429a 100644
--- a/pkgs/development/ocaml-modules/irmin/test.nix
+++ b/pkgs/development/ocaml-modules/irmin/test.nix
@@ -8,7 +8,6 @@ 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 ddfc0d073205..82a89daec359 100644
--- a/pkgs/development/ocaml-modules/irmin/tezos.nix
+++ b/pkgs/development/ocaml-modules/irmin/tezos.nix
@@ -7,7 +7,6 @@ buildDunePackage rec {
   pname = "irmin-tezos";
 
   inherit (irmin) version src strictDeps;
-  duneVersion = "3";
 
   propagatedBuildInputs = [
     irmin