diff --git a/packages/duff/duff.0.3/opam b/packages/duff/duff.0.3/opam
new file mode 100644
index 00000000000..d6be7b9b9db
--- /dev/null
+++ b/packages/duff/duff.0.3/opam
@@ -0,0 +1,39 @@
+opam-version: "2.0"
+maintainer:   "Romain Calascibetta <romain.calascibetta@gmail.com>"
+authors:      "Romain Calascibetta <romain.calascibetta@gmail.com>"
+homepage:     "https://github.com/mirage/duff"
+bug-reports:  "https://github.com/mirage/duff/issues"
+dev-repo:     "git+https://github.com/mirage/duff.git"
+doc:          "https://mirage.github.io/duff/"
+license:      "MIT"
+synopsis:     "Rabin's fingerprint and diff algorithm in OCaml"
+description: """
+This library provides a pure implementation of Rabin's fingerprint and diff algorithm in OCaml.
+
+It follows libXdiff C library. It is used by ocaml-git project.
+"""
+
+build: [
+  ["dune" "build" "-p" name "-j" jobs]
+  ["dune" "runtest" "-p" name "-j" jobs] {with-test}
+]
+
+depends: [
+  "ocaml"    {>= "4.03.0"}
+  "dune"     {>= "2.0.0"}
+  "fmt"
+  "bigarray-compat"
+  "stdlib-shims"
+  "alcotest"    {with-test}
+  "bigstringaf" {with-test}
+  "hxd"         {with-test}
+  "crowbar"     {with-test}
+]
+
+url {
+  src: "https://github.com/mirage/duff/releases/download/v0.3/duff-v0.3.tbz"
+  checksum: [
+    "sha256=d5fee97be9ce3183375fe2e8df8d44be176997e47ac47049922e8e34bb3f66d1"
+    "sha512=406e137dba3a8c16460b25d0c5f757823e9c53ec40cc8f9538bf2d05e693b4af016801346a72b1c934577432eb506f5d63e65cf53cf5e85f09a90ee4cb40c0b2"
+  ]
+}
diff --git a/packages/git/git.2.0.0/opam b/packages/git/git.2.0.0/opam
index 758e6b42dfb..68c80e76d50 100644
--- a/packages/git/git.2.0.0/opam
+++ b/packages/git/git.2.0.0/opam
@@ -35,7 +35,7 @@ depends: [
   "decompress" {>= "0.8.1" & < "0.9.0"}
   "checkseum"  {>= "0.0.3"}
   "encore"     {< "0.3"}
-  "duff"
+  "duff"       {< "0.3"}
   "hex"
   "ocplib-endian"
   "rresult"
diff --git a/packages/git/git.2.1.0/opam b/packages/git/git.2.1.0/opam
index 2f41e2727cb..3e778d58502 100644
--- a/packages/git/git.2.1.0/opam
+++ b/packages/git/git.2.1.0/opam
@@ -36,7 +36,7 @@ depends: [
   "checkseum"  {>= "0.1.0"}
   "ke"
   "encore" {< "0.6"}
-  "duff"
+  "duff" {< "0.3"}
   "hex"
   "ocplib-endian"
   "rresult"
diff --git a/packages/git/git.2.1.1/opam b/packages/git/git.2.1.1/opam
index b6c9f3cde8d..e0d516c4e23 100644
--- a/packages/git/git.2.1.1/opam
+++ b/packages/git/git.2.1.1/opam
@@ -37,7 +37,7 @@ depends: [
   "stdlib-shims"
   "ke"
   "encore" {< "0.6"}
-  "duff"
+  "duff" {< "0.3"}
   "hex"
   "ocplib-endian"
   "rresult"
diff --git a/packages/git/git.2.1.2/opam b/packages/git/git.2.1.2/opam
index c4ad299001c..be68ca17d34 100644
--- a/packages/git/git.2.1.2/opam
+++ b/packages/git/git.2.1.2/opam
@@ -37,7 +37,7 @@ depends: [
   "stdlib-shims"
   "ke"
   "encore" {< "0.6"}
-  "duff"
+  "duff" {< "0.3"}
   "hex"
   "ocplib-endian"
   "rresult"
diff --git a/packages/git/git.2.1.3/opam b/packages/git/git.2.1.3/opam
index 9a200afdc2c..228c066df38 100644
--- a/packages/git/git.2.1.3/opam
+++ b/packages/git/git.2.1.3/opam
@@ -37,7 +37,7 @@ depends: [
   "stdlib-shims"
   "ke"
   "encore"     {>= "0.5" & < "0.6"}
-  "duff"
+  "duff" {< "0.3"}
   "hex"
   "ocplib-endian"
   "rresult"