diff --git a/pkgs/development/ocaml-modules/index/default.nix b/pkgs/development/ocaml-modules/index/default.nix
index b1141f814a89..d0857f7ef0a1 100644
--- a/pkgs/development/ocaml-modules/index/default.nix
+++ b/pkgs/development/ocaml-modules/index/default.nix
@@ -1,16 +1,17 @@
-{ lib, fetchurl, buildDunePackage, fmt, logs }:
+{ lib, fetchurl, buildDunePackage, fmt, logs, stdlib-shims }:
 
 buildDunePackage rec {
   pname = "index";
-  version = "1.0.1";
+  version = "1.2.0";
 
   minimumOCamlVersion = "4.07";
 
   src = fetchurl {
     url = "https://github.com/mirage/index/releases/download/${version}/index-${version}.tbz";
-    sha256 = "1006wr3g21s4j2vsd73gphhkrh1fy4swh6gqvlsa9c6q7vz9wbvz";
+    sha256 = "0d44s1d2mpxvpg0zh57c928wf1w1wd33l1fw5r62al5zmi710ff6";
   };
 
+  buildInputs = [ stdlib-shims ];
   propagatedBuildInputs = [ fmt logs ];
 
   meta = {
diff --git a/pkgs/development/ocaml-modules/irmin/default.nix b/pkgs/development/ocaml-modules/irmin/default.nix
index 2db57671177f..cba677591676 100644
--- a/pkgs/development/ocaml-modules/irmin/default.nix
+++ b/pkgs/development/ocaml-modules/irmin/default.nix
@@ -6,13 +6,13 @@
 buildDunePackage rec {
 
   pname = "irmin";
-  version = "2.0.0";
+  version = "2.1.0";
 
-  minimumOCamlVersion = "4.06";
+  minimumOCamlVersion = "4.07";
 
   src = fetchurl {
     url = "https://github.com/mirage/irmin/releases/download/${version}/irmin-${version}.tbz";
-    sha256 = "09qffvgi5yrm3ghiywlbdhjly8xb5x5njnan213q8j033fzmf2dr";
+    sha256 = "1ji8r7zbdmhbk8r8w2hskd9z7pnvirzbhincfxndxgdaxbfkff5g";
   };
 
   propagatedBuildInputs = [ astring base64 digestif fmt jsonm logs ocaml_lwt ocamlgraph uri ];
diff --git a/pkgs/development/ocaml-modules/irmin/pack.nix b/pkgs/development/ocaml-modules/irmin/pack.nix
index 4eacc719cec0..c374b1a22750 100644
--- a/pkgs/development/ocaml-modules/irmin/pack.nix
+++ b/pkgs/development/ocaml-modules/irmin/pack.nix
@@ -1,12 +1,13 @@
-{ lib, buildDunePackage, alcotest-lwt, index, irmin, irmin-test }:
+{ lib, buildDunePackage, alcotest-lwt, index, irmin, irmin-test, ocaml_lwt }:
 
 buildDunePackage rec {
+  minimumOCamlVersion = "4.02.3";
 
   pname = "irmin-pack";
 
   inherit (irmin) version src;
 
-  propagatedBuildInputs = [ index irmin ];
+  propagatedBuildInputs = [ index irmin ocaml_lwt ];
 
   checkInputs = lib.optionals doCheck [ alcotest-lwt irmin-test ];
 
diff --git a/pkgs/development/ocaml-modules/irmin/ppx.nix b/pkgs/development/ocaml-modules/irmin/ppx.nix
new file mode 100644
index 000000000000..c28532b49a9e
--- /dev/null
+++ b/pkgs/development/ocaml-modules/irmin/ppx.nix
@@ -0,0 +1,14 @@
+{ lib, buildDunePackage, ppxlib, ocaml-syntax-shims, irmin }:
+
+buildDunePackage {
+  pname = "ppx_irmin";
+
+  inherit (irmin) version src minimumOCamlVersion;
+
+  buildInputs = [ ocaml-syntax-shims ];
+  propagatedBuildInputs = [ ppxlib ];
+
+  meta = irmin.meta // {
+    description = "PPX deriver for Irmin generics";
+  };
+}
diff --git a/pkgs/development/ocaml-modules/ocaml-syntax-shims/default.nix b/pkgs/development/ocaml-modules/ocaml-syntax-shims/default.nix
new file mode 100644
index 000000000000..706dc913e1e6
--- /dev/null
+++ b/pkgs/development/ocaml-modules/ocaml-syntax-shims/default.nix
@@ -0,0 +1,24 @@
+{ stdenv, buildDunePackage, fetchurl }:
+
+buildDunePackage rec {
+  minimumOCamlVersion = "4.02.3";
+
+  pname = "ocaml-syntax-shims";
+  version = "1.0.0";
+
+  src = fetchurl {
+    url = "https://github.com/ocaml-ppx/${pname}/releases/download/${version}/${pname}-${version}.tbz";
+    sha256 = "1j7848khli4p7j8i2kmnvhdnhcwhy3zgdpf5ds5ic30ax69y3cl9";
+  };
+
+  useDune2 = true;
+
+  doCheck = true;
+
+  meta = with stdenv.lib; {
+    homepage = "https://github.com/ocaml-ppx/ocaml-syntax-shims";
+    description = "Backport new syntax to older OCaml versions";
+    license = licenses.mit;
+    maintainers = with maintainers; [ sternenseemann ];
+  };
+}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index d3f02912f531..bef843ed32a6 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -645,6 +645,8 @@ let
 
     ocaml_sqlite3 = callPackage ../development/ocaml-modules/sqlite3 { };
 
+    ocaml-syntax-shims = callPackage ../development/ocaml-modules/ocaml-syntax-shims { };
+
     syslog = callPackage ../development/ocaml-modules/syslog { };
 
     ocaml_text = callPackage ../development/ocaml-modules/ocaml-text { };
@@ -822,6 +824,10 @@ let
 
     ppx_import = callPackage ../development/ocaml-modules/ppx_import {};
 
+    ppx_irmin = callPackage ../development/ocaml-modules/irmin/ppx.nix {
+      ppxlib = ppxlib.override { version = "0.12.0"; };
+    };
+
     ppx_sqlexpr = callPackage ../development/ocaml-modules/sqlexpr/ppx.nix {};
 
     ppx_tools =