diff --git a/pkgs/development/ocaml-modules/topkg/default.nix b/pkgs/development/ocaml-modules/topkg/default.nix
index 3e6b78a71719..e28a86907bb4 100644
--- a/pkgs/development/ocaml-modules/topkg/default.nix
+++ b/pkgs/development/ocaml-modules/topkg/default.nix
@@ -22,11 +22,11 @@ in
 
 stdenv.mkDerivation rec {
   name = "ocaml${ocaml.version}-topkg-${version}";
-  version = "0.9.1";
+  version = "1.0.0";
 
   src = fetchurl {
     url = "http://erratique.ch/software/topkg/releases/topkg-${version}.tbz";
-    sha256 = "1slrzbmyp81xhgsfwwqs2d6gxzvqx0gcp34rq00h5iblhcq7myx6";
+    sha256 = "1df61vw6v5bg2mys045682ggv058yqkqb67w7r2gz85crs04d5fw";
   };
 
   buildInputs = [ ocaml findlib ocamlbuild ];