diff --git a/pkgs/development/ocaml-modules/camlpdf/default.nix b/pkgs/development/ocaml-modules/camlpdf/default.nix
index 18683d5f1709..f496ce91c826 100644
--- a/pkgs/development/ocaml-modules/camlpdf/default.nix
+++ b/pkgs/development/ocaml-modules/camlpdf/default.nix
@@ -5,27 +5,17 @@ then throw "camlpdf is not available for OCaml ${ocaml.version}"
 else
 
 stdenv.mkDerivation rec {
-  version = "2.3.1";
+  version = "2.4";
   name = "ocaml${ocaml.version}-camlpdf-${version}";
   src = fetchFromGitHub {
     owner = "johnwhitington";
     repo = "camlpdf";
     rev = "v${version}";
-    sha256 = "1q69hhk63z836jbkv4wsng27w35w0qpz01c7ax0mqm8d8kmnr0v4";
+    sha256 = "09kzrgmlxb567315p3fy59ba0kv7xhp548n9i3l4wf9n06p0ww9m";
   };
 
   buildInputs = [ which ocaml findlib ];
 
-  # Version number in META file is wrong
-  patchPhase = ''
-    patch -p 0 META <<EOF
-    3c3
-    < version="1.7.1"
-    ---
-    > version="${version}"
-    EOF
-  '';
-
   preInstall = ''
     mkdir -p $out/lib/ocaml/${ocaml.version}/site-lib/stublibs
   '';
diff --git a/pkgs/development/ocaml-modules/cpdf/default.nix b/pkgs/development/ocaml-modules/cpdf/default.nix
index cc2aad52d3d6..2a0fae4a1dbb 100644
--- a/pkgs/development/ocaml-modules/cpdf/default.nix
+++ b/pkgs/development/ocaml-modules/cpdf/default.nix
@@ -1,6 +1,10 @@
 { lib, stdenv, fetchFromGitHub, ocaml, findlib, camlpdf, ncurses }:
 
-let version = "2.3.1"; in
+if !lib.versionAtLeast ocaml.version "4.10"
+then throw "cpdf is not available for OCaml ${ocaml.version}"
+else
+
+let version = "2.4"; in
 
 stdenv.mkDerivation {
   name = "ocaml${ocaml.version}-cpdf-${version}";
@@ -9,19 +13,14 @@ stdenv.mkDerivation {
     owner = "johnwhitington";
     repo = "cpdf-source";
     rev = "v${version}";
-    sha256 = "1gwz0iy28f67kbqap2q10nf98dalwbi03vv5j893z2an7pb4w68z";
+    sha256 = "1a8lmfc76dr8x6pxgm4aypbys02pfma9yh4z3l1qxp2q1909na5l";
   };
 
-  prePatch = ''
-    substituteInPlace META --replace 'version="1.7"' 'version="${version}"'
-  '';
-
   buildInputs = [ ocaml findlib ncurses ];
   propagatedBuildInputs = [ camlpdf ];
 
-  createFindlibDestdir = true;
-
-  postInstall = ''
+  preInstall = ''
+    mkdir -p $OCAMLFIND_DESTDIR
     mkdir -p $out/bin
     cp cpdf $out/bin
     mkdir -p $out/share/