diff --git a/pkgs/development/compilers/ats2/default.nix b/pkgs/development/compilers/ats2/default.nix
index e8c3af5d7e1..f8de9f57b5d 100644
--- a/pkgs/development/compilers/ats2/default.nix
+++ b/pkgs/development/compilers/ats2/default.nix
@@ -3,11 +3,11 @@
 , withContrib ? true }:
 
 let
-  versionPkg = "0.4.1" ;
+  versionPkg = "0.4.2";
 
   contrib = fetchurl {
     url = "mirror://sourceforge/ats2-lang/ATS2-Postiats-contrib-${versionPkg}.tgz";
-    sha256 = "184m4hz2xszhcfc6w9fw9qibhmcvgjmikwfwkb345xypr59jm93d";
+    hash = "sha256-m0hfBLsaNiLaIktcioK+ZtWUsWht3IDSJ6CzgJmS06c=";
   };
 
   postInstallContrib = lib.optionalString withContrib
@@ -31,7 +31,7 @@ stdenv.mkDerivation rec {
 
   src = fetchurl {
     url = "mirror://sourceforge/ats2-lang/ATS2-Postiats-gmp-${version}.tgz";
-    sha256 = "0c4nqp6yzmpj0mcpg7ibmwyqi8hjw3sza8myvy4nzq3fa6wldy5l";
+    hash = "sha256-UWgDjFojPBYgykrCrJyYvVWY+Gc5d4aRGjTWjc528AM=";
   };
 
   buildInputs = [ gmp ];