I bet Unreal Engine 4 support for Wii U appeared in the Unreal Developer Network, when you logged in as a licensed dev for the system, it seems only UE3 was available, and now UE4 may be there too.
Read my original story on Fictionpress (Shinigami Twin): http://www.fictionpress.com/s/2996503/1/Shinigami-Twin
As well as my other one (Hell's Punishment): http://www.fictionpress.com/s/3085054/1/Hell-s-Punishment
Nintendo Network ID: kingofe3