diff --git a/pkgs/development/python-modules/werkzeug/default.nix b/pkgs/development/python-modules/werkzeug/default.nix
index 9496d51bfc1..19945785eed 100644
--- a/pkgs/development/python-modules/werkzeug/default.nix
+++ b/pkgs/development/python-modules/werkzeug/default.nix
@@ -4,18 +4,18 @@
 
 buildPythonPackage rec {
   pname = "Werkzeug";
-  version = "0.14.1";
+  version = "0.15.1";
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "c3fd7a7d41976d9f44db327260e263132466836cef6f91512889ed60ad26557c";
+    sha256 = "ca5c2dcd367d6c0df87185b9082929d255358f5391923269335782b213d52655";
   };
 
   propagatedBuildInputs = [ itsdangerous ];
-  checkInputs = [ pytest requests glibcLocales hypothesis ];
+  checkInputs = [ pytest requests hypothesis ];
 
   checkPhase = ''
-    LC_ALL="en_US.UTF-8" py.test ${stdenv.lib.optionalString stdenv.isDarwin "-k 'not test_get_machine_id'"}
+    pytest ${stdenv.lib.optionalString stdenv.isDarwin "-k 'not test_get_machine_id'"}
   '';
 
   meta = with stdenv.lib; {