This date only applies to the Mac, PC, PlayStation 4, PlayStation 3, Wii U Xbox One, and Xbox 360 versions of the game, with the 3DS and Vita ports scheduled to come “at a later point,” according to a post on the Mighty No. 9 blog.
Mighty No. 9 was announced three years ago as part of a Kickstarter campaign by Mega Man creator Keiji Inafune, and is widely considered to be a spiritual successor to the sidescrolling series.
For more on Mighty No. 9, check out our latest preview