Nintendo has confirmed (via Kotaku) that it will be ending production of Wii U hardware in Japan on their official website, This news comes hot on the heels of rumours that had speculated that Nintendo would be pulling the plug on the hardware soon (rumours that Nintendo had, incidentally, denied at the time)- now it looks like there was more truth to them than Nintendo wanted to admit.
Presuming discontinuation some time later this month, the Wii U will have spent four years in active production- which is a dismally short life for it, but is also the minimum permissible amount for a console (the Sega Saturn and the original Xbox were both in production for four years as well). The four years were besotted with problems, and the Wii U never managed to find its identity or do well- but in that period, it did end up with an enviable number of good games.
The Wii U is scheduled to be replaced by the Nintendo Switch come March. Meanwhile, the Nintendo 3DS, which launched back in March 2011, trucks on (and is in fact scheduled to get a major price drop and new game release this November).