diff --git a/pkgs/development/tools/ocaml/cppo/default.nix b/pkgs/development/tools/ocaml/cppo/default.nix
index fc5f2e4a688b..d6327010e30e 100644
--- a/pkgs/development/tools/ocaml/cppo/default.nix
+++ b/pkgs/development/tools/ocaml/cppo/default.nix
@@ -7,8 +7,8 @@ assert stdenv.lib.versionAtLeast ocaml.version "3.12";
 
 let param =
   if stdenv.lib.versionAtLeast ocaml.version "4.02" then {
-    version = "1.6.6";
-    sha256 = "1smcc0l6fh2n0y6bp96c69j5nw755jja99w0b206wx3yb2m4w2hs";
+    version = "1.6.5";
+    sha256 = "03c0amszy28shinvz61hm340jz446zz5763a1pdqlza36kwcj0p0";
     buildInputs = [ dune ];
     extra = {
       inherit (dune) installPhase;
@@ -31,7 +31,7 @@ stdenv.mkDerivation ({
   name = "${pname}-${param.version}";
 
   src = fetchFromGitHub {
-    owner = "ocaml-community";
+    owner = "mjambon";
     repo = pname;
     rev = "v${param.version}";
     inherit (param) sha256;