diff --git a/pkgs/development/ocaml-modules/cmdliner/default.nix b/pkgs/development/ocaml-modules/cmdliner/1_0.nix
similarity index 97%
rename from pkgs/development/ocaml-modules/cmdliner/default.nix
rename to pkgs/development/ocaml-modules/cmdliner/1_0.nix
index ed96b1b61553..718c6b95a069 100644
--- a/pkgs/development/ocaml-modules/cmdliner/default.nix
+++ b/pkgs/development/ocaml-modules/cmdliner/1_0.nix
@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
   meta = with lib; {
     homepage = "https://erratique.ch/software/cmdliner";
     description = "An OCaml module for the declarative definition of command line interfaces";
-    license = licenses.bsd3;
+    license = licenses.isc;
     inherit (ocaml.meta) platforms;
     maintainers = [ maintainers.vbgl ];
   };
diff --git a/pkgs/development/ocaml-modules/cmdliner/1_1.nix b/pkgs/development/ocaml-modules/cmdliner/1_1.nix
new file mode 100644
index 000000000000..001d967fca1b
--- /dev/null
+++ b/pkgs/development/ocaml-modules/cmdliner/1_1.nix
@@ -0,0 +1,32 @@
+{ lib, stdenv, fetchurl, ocaml, findlib, ocamlbuild, topkg, result }:
+
+stdenv.mkDerivation rec {
+  pname = "cmdliner";
+  version = "1.1.1";
+
+  src = fetchurl {
+    url = "https://erratique.ch/software/${pname}/releases/${pname}-${version}.tbz";
+    sha256 = "sha256-oa6Hw6eZQO+NHdWfdED3dtHckm4BmEbdMiAuRkYntfs=";
+  };
+
+  minimalOCamlVersion = "4.08";
+  nativeBuildInputs = [ ocaml ];
+
+  makeFlags = [ "PREFIX=$(out)" ];
+  installTargets = "install install-doc";
+  installFlags = [
+    "LIBDIR=$(out)/lib/ocaml/${ocaml.version}/site-lib/${pname}"
+    "DOCDIR=$(out)/share/doc/${pname}"
+  ];
+  postInstall = ''
+    mv $out/lib/ocaml/${ocaml.version}/site-lib/${pname}/{opam,${pname}.opam}
+  '';
+
+  meta = with lib; {
+    homepage = "https://erratique.ch/software/cmdliner";
+    description = "An OCaml module for the declarative definition of command line interfaces";
+    license = licenses.isc;
+    inherit (ocaml.meta) platforms;
+    maintainers = [ maintainers.vbgl ];
+  };
+}
diff --git a/pkgs/development/tools/ocaml/ocamlformat/default.nix b/pkgs/development/tools/ocaml/ocamlformat/default.nix
index 096fe1b4324a..5847f18ba3d9 100644
--- a/pkgs/development/tools/ocaml/ocamlformat/default.nix
+++ b/pkgs/development/tools/ocaml/ocamlformat/default.nix
@@ -68,5 +68,9 @@ rec {
     version = "0.20.1";
   };
 
-  ocamlformat = ocamlformat_0_20_1;
+  ocamlformat_0_21_0 = mkOCamlformat {
+    version = "0.21.0";
+  };
+
+  ocamlformat = ocamlformat_0_21_0;
 }
diff --git a/pkgs/development/tools/ocaml/ocamlformat/generic.nix b/pkgs/development/tools/ocaml/ocamlformat/generic.nix
index 517ca6585fe1..7eee57e9abcc 100644
--- a/pkgs/development/tools/ocaml/ocamlformat/generic.nix
+++ b/pkgs/development/tools/ocaml/ocamlformat/generic.nix
@@ -25,6 +25,7 @@ let src =
       "0.19.0" = "0ihgwl7d489g938m1jvgx8azdgq9f5np5mzqwwya797hx2m4dz32";
       "0.20.0" = "sha256-JtmNCgwjbCyUE4bWqdH5Nc2YSit+rekwS43DcviIfgk=";
       "0.20.1" = "sha256-fTpRZFQW+ngoc0T6A69reEUAZ6GmHkeQvxspd5zRAjU=";
+      "0.21.0" = "sha256-KhgX9rxYH/DM6fCqloe4l7AnJuKrdXSe6Y1XY3BXMy0=";
     }."${version}";
   };
   ocamlPackages =
@@ -60,7 +61,7 @@ buildDunePackage {
     if lib.versionAtLeast version "0.20.0"
     then [
       base
-      cmdliner
+      (if lib.versionAtLeast version "0.21.0" then cmdliner_1_1 else cmdliner_1_0)
       dune-build-info
       either
       fix
@@ -78,7 +79,7 @@ buildDunePackage {
     else if lib.versionAtLeast version "0.19.0"
     then [
       base
-      cmdliner
+      cmdliner_1_0
       fpath
       re
       stdio
@@ -94,7 +95,7 @@ buildDunePackage {
     else if lib.versionAtLeast version "0.18.0"
     then [
       base
-      cmdliner
+      cmdliner_1_0
       fpath
       odoc
       re
@@ -112,7 +113,7 @@ buildDunePackage {
     else if lib.versionAtLeast version "0.17.0"
     then [
       base
-      cmdliner
+      cmdliner_1_0
       fpath
       odoc
       re
@@ -131,7 +132,7 @@ buildDunePackage {
     else if lib.versionAtLeast version "0.15.1"
     then [
       base
-      cmdliner
+      cmdliner_1_0
       fpath
       odoc
       re
@@ -148,7 +149,7 @@ buildDunePackage {
     else if lib.versionAtLeast version "0.14"
     then [
       base
-      cmdliner
+      cmdliner_1_0
       fpath
       ocaml-migrate-parsetree
       odoc
@@ -161,7 +162,7 @@ buildDunePackage {
       menhirSdk
     ] else [
       base
-      cmdliner
+      cmdliner_1_0
       fpath
       ocaml-migrate-parsetree
       odoc
@@ -178,4 +179,3 @@ buildDunePackage {
     license = lib.licenses.mit;
   };
 }
-
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 281b0fd328dd..8d59013e7419 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -13568,7 +13568,7 @@ with pkgs;
     ocamlformat_0_11_0 ocamlformat_0_12 ocamlformat_0_13_0 ocamlformat_0_14_0
     ocamlformat_0_14_1 ocamlformat_0_14_2 ocamlformat_0_14_3 ocamlformat_0_15_0
     ocamlformat_0_15_1 ocamlformat_0_16_0 ocamlformat_0_17_0 ocamlformat_0_18_0
-    ocamlformat_0_19_0 ocamlformat_0_20_0 ocamlformat_0_20_1;
+    ocamlformat_0_19_0 ocamlformat_0_20_0 ocamlformat_0_20_1 ocamlformat_0_21_0;
 
   orc = callPackage ../development/compilers/orc { };
 
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index a1effc538b60..3bbfd736f7f0 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -177,7 +177,13 @@ let
 
     cil = callPackage ../development/ocaml-modules/cil { };
 
-    cmdliner = callPackage ../development/ocaml-modules/cmdliner { };
+    cmdliner_1_0 = callPackage ../development/ocaml-modules/cmdliner/1_0.nix { };
+
+    cmdliner_1_1 = callPackage ../development/ocaml-modules/cmdliner/1_1.nix { };
+
+    # The 1.1.0 release broke a lot of packages and is not compatible with
+    # OCaml < 4.08.
+    cmdliner = cmdliner_1_0;
 
     cohttp = callPackage ../development/ocaml-modules/cohttp { };