diff --git a/pkgs/development/ocaml-modules/cstruct/async.nix b/pkgs/development/ocaml-modules/cstruct/async.nix
index 57647c97c41..1fe020f6490 100644
--- a/pkgs/development/ocaml-modules/cstruct/async.nix
+++ b/pkgs/development/ocaml-modules/cstruct/async.nix
@@ -4,6 +4,8 @@ buildDunePackage rec {
   pname = "cstruct-async";
   inherit (cstruct) src version meta;
 
+  duneVersion = "3";
+
   propagatedBuildInputs = [
     async_unix
     async
diff --git a/pkgs/development/ocaml-modules/cstruct/default.nix b/pkgs/development/ocaml-modules/cstruct/default.nix
index 9efe75af70c..9877adbcf81 100644
--- a/pkgs/development/ocaml-modules/cstruct/default.nix
+++ b/pkgs/development/ocaml-modules/cstruct/default.nix
@@ -2,13 +2,14 @@
 
 buildDunePackage rec {
   pname = "cstruct";
-  version = "6.1.1";
+  version = "6.2.0";
 
   minimalOCamlVersion = "4.08";
+  duneVersion = "3";
 
   src = fetchurl {
     url = "https://github.com/mirage/ocaml-cstruct/releases/download/v${version}/cstruct-${version}.tbz";
-    sha256 = "sha256-G3T5hw9qfuYAiSRZBxbdUzpyijyhC7GNqf6ovkZ/UY0=";
+    hash = "sha256-mngHM5JYDoNJFI+jq0sbLpidydMNB0AbBMlrfGDwPmI=";
   };
 
   buildInputs = [ fmt ];
diff --git a/pkgs/development/ocaml-modules/cstruct/lwt.nix b/pkgs/development/ocaml-modules/cstruct/lwt.nix
index 7226193565b..3aa70e5c998 100644
--- a/pkgs/development/ocaml-modules/cstruct/lwt.nix
+++ b/pkgs/development/ocaml-modules/cstruct/lwt.nix
@@ -9,6 +9,7 @@ else
     inherit (cstruct) version src meta;
 
     minimalOCamlVersion = "4.08";
+    duneVersion = "3";
 
     propagatedBuildInputs = [ cstruct lwt ];
   }
diff --git a/pkgs/development/ocaml-modules/cstruct/ppx.nix b/pkgs/development/ocaml-modules/cstruct/ppx.nix
index b640c9745f3..f2b19355b09 100644
--- a/pkgs/development/ocaml-modules/cstruct/ppx.nix
+++ b/pkgs/development/ocaml-modules/cstruct/ppx.nix
@@ -11,6 +11,7 @@ else
     inherit (cstruct) version src meta;
 
     minimalOCamlVersion = "4.08";
+    duneVersion = "3";
 
     propagatedBuildInputs = [ cstruct ppxlib sexplib stdlib-shims ];
 
diff --git a/pkgs/development/ocaml-modules/cstruct/sexp.nix b/pkgs/development/ocaml-modules/cstruct/sexp.nix
index a20911cbb29..3b28cda15af 100644
--- a/pkgs/development/ocaml-modules/cstruct/sexp.nix
+++ b/pkgs/development/ocaml-modules/cstruct/sexp.nix
@@ -9,6 +9,7 @@ buildDunePackage rec {
   inherit (cstruct) version src meta;
 
   minimalOCamlVersion = "4.08";
+  duneVersion = "3";
 
   doCheck = true;
   checkInputs = [ alcotest ];
diff --git a/pkgs/development/ocaml-modules/cstruct/unix.nix b/pkgs/development/ocaml-modules/cstruct/unix.nix
index 064bdadb328..40467a77a57 100644
--- a/pkgs/development/ocaml-modules/cstruct/unix.nix
+++ b/pkgs/development/ocaml-modules/cstruct/unix.nix
@@ -9,6 +9,7 @@ else
     inherit (cstruct) version src meta;
 
     minimalOCamlVersion = "4.08";
+    duneVersion = "3";
 
     propagatedBuildInputs = [ cstruct ];
   }