diff --git a/pkgs/development/ocaml-modules/sedlex/default.nix b/pkgs/development/ocaml-modules/sedlex/default.nix
index 6fcdb5ec6fa4..1e3cb02b913a 100644
--- a/pkgs/development/ocaml-modules/sedlex/default.nix
+++ b/pkgs/development/ocaml-modules/sedlex/default.nix
@@ -1,17 +1,19 @@
-{ stdenv, fetchzip, ocaml, findlib, gen, ppx_tools }:
+{ stdenv, fetchzip, ocaml, findlib, gen, ppx_tools_versioned }:
 
-assert stdenv.lib.versionAtLeast ocaml.version "4.02";
+if !stdenv.lib.versionAtLeast ocaml.version "4.02"
+then throw "sedlex is not available for OCaml ${ocaml.version}"
+else
 
 stdenv.mkDerivation rec {
   name = "ocaml${ocaml.version}-sedlex-${version}";
-  version = "1.99.3";
+  version = "1.99.4";
 
   src = fetchzip {
     url = "http://github.com/alainfrisch/sedlex/archive/v${version}.tar.gz";
-    sha256 = "1wghjy3qyj43ll1ikchlqy7fv2hxcn3ap9xgsscm2ch09d8dcv7y";
+    sha256 = "1b7nqxyfcz8i7m4b8zil2rn6ygh2czy26f9v64xnxn8r0hy9sh1m";
   };
 
-  buildInputs = [ ocaml findlib ppx_tools ];
+  buildInputs = [ ocaml findlib ppx_tools_versioned ];
 
   propagatedBuildInputs = [ gen ];