The Uplay application is no longer accessible in the WiiU.
You can still connect to the Ubisoft mobile application or to the Ubisoft Club website to get rewards for your WiiU games. All rewards you redeemed for your WiiU games remain yours. To finish well our presence on the WiiU, all players who have completed a challenge or redeemed a reward on the Wii U since January 2018 will get 40 Club Units.
As usual, you can use your Club Units on any other Ubisoft game on any other platform.
Of course, if you have any question, please don't hesitate to get in touch with our support teams.