diff --git a/pkgs/development/ocaml-modules/cpdf/default.nix b/pkgs/development/ocaml-modules/cpdf/default.nix
index d9960f732c74..e919f3b56157 100644
--- a/pkgs/development/ocaml-modules/cpdf/default.nix
+++ b/pkgs/development/ocaml-modules/cpdf/default.nix
@@ -6,13 +6,13 @@ else
 
 stdenv.mkDerivation rec {
   pname = "ocaml${ocaml.version}-cpdf";
-  version = "2.5";
+  version = "2.5.1";
 
   src = fetchFromGitHub {
     owner = "johnwhitington";
     repo = "cpdf-source";
     rev = "v${version}";
-    sha256 = "sha256:1qmx229nij7g6qmiacmyy4mcgx3k9509p4slahivshqm79d6wiwl";
+    hash = "sha256-B1wYLcxTRUyzREtE9uvPMwSiwtB+q0RQsY02F0u3aa0=";
   };
 
   nativeBuildInputs = [ ocaml findlib ];