diff --git a/pkgs/development/compilers/urweb/default.nix b/pkgs/development/compilers/urweb/default.nix
index c1e1e2ece7a..7145a8f2fa0 100644
--- a/pkgs/development/compilers/urweb/default.nix
+++ b/pkgs/development/compilers/urweb/default.nix
@@ -4,11 +4,11 @@
 
 stdenv.mkDerivation rec {
   name = "urweb-${version}";
-  version = "20170105";
+  version = "20170720";
 
   src = fetchurl {
     url = "http://www.impredicative.com/ur/${name}.tgz";
-    sha256 = "2ad3aea2c4851c9b18f752d38c7127af8293fbbbbdb3dd06b73a4603fe399b67";
+    sha256 = "17qh9mcmlhbv6r52yij8l9ik7j7x6x7c09lf6pznnbdh4sf8p5wb";
   };
 
   buildInputs = [ openssl mlton mysql.client postgresql sqlite ];