The game was originally announced in January 2013 by game producer Eiji Aonuma for the Wii U system and was set to launch holiday 2015. After various delays, it was announced that Zelda would be released on both the Wii U and the upcoming Nintendo Switch sometime in 2017.
Shifting the development to the more powerful Switch may have been due to the technical limitations of the Wii U. There were some complaints from early gameplay of Zelda: BotW regarding framerate issues, but these could have been chalked up to an un-optimized demo build.
Since these are unconfirmed rumors at the time of this writing, we can’t say if this is true or not. Once the smoke has cleared from this and we get some official word from Nintendo or confirmation from a trusted insider, we will report further on this development.