Wii U system software 2.1.3U is now available for users to download. The update doesn’t appear to bring any major changes other than behind the scenes modifications. Nonetheless it would wise to get to downloading it right away.
With past system updates to go by you should make sure your internet connection is stable to prevent your console from losing connection during the update process. While this update doesn’t appear to take as long to download as past versions you should always prepare for the worst.