A software update is now available that makes several adjustments to enhance the overall experience. Please start the game while your Wii U console is connected to the internet to update the software. The software version after this update will be 1.0.1, as shown in the screenshot below.
Please note: this update is required in order to use Mario Tennis: Ultra Smash's online features.
Introduces additional enhancements to improve the user’s experience and enjoyment
Downloading updates will not affect any of your saved data.