Nintendo has long since stopped updating the console.The last firmware update was January 2016, not including the fall 2017 update which did nothing but close a piracy exploit with the wii u's internet browser.If you don't refuse, your Wii upgrades and your Homebrew Channel disappears.You need to know what version of the OS you upgraded to.Updates, which are downloaded via the system's Internet connection, allow Nintendo to add and remove features and software.
Likely cause: Your wireless router may need to be power cycled, or the connection settings have changed.
Yacht Club Games continues to promise that the Wii U will receive any and all Shovel Knight updates, including those supporting the new Amiibo 3-pack announced last year.
Freedom Planet just received an additional playable character as promised.
An accidental upgrade is most likely to happen if you play a game that includes an update check and you haven't disabled Wii's update checking.
When a new Wii update is available from Nintendo, you are notified, but you can refuse the update.