Nintendo does occasionally have humorous timing, releasing a new system update for the Wii U on 1st April. It's real though, we can assure you of that, and is a relatively small download that should download and install within five minutes on a solid connection.
As always the Nintendo support website provides a changelog, with this one merely specifying more stability and adjustments.
Improvements to system stability and usability:
Further improvements to overall system stability and other minor adjustments have been made to enhance the user experience.
Just how stable can the Wii U get? It's a question for the ages, though jesting aside it's pleasing to see Nintendo keeping active with maintenance on the system. Considering its April Fools' arrival we haven't seen any hidden jokes or gags related to this update, so you can download with comfort.
It's available in North America, Europe and Australia right now, so grab it while it's hot.