Nothing of note really.
From: Nintendo
Version 5.5.0 U, available via an Internet connection, includes the following improvements:
Changes to the Wii U Menu and HOME Menu:
- The Nintendo TVii icon has been removed from the Wii U Menu and HOME Menu. For more information regarding the end of this service, click here.
Improvements to system stability and usability:
- Further improvements to overall system stability and other minor adjustments have been made to enhance the user experience