Source: http://www.joystiq.com/2014/08/29/ninte ... ds-3ds-xl/
Nintendo it is releasing a new 3DS and 3DS-XL in Japan that has an integrated second analog stick and a slew of other upgrades that are listed in the article. Due to the changes, some of the new games that take advantage of the new features will not be compatible with the older 3DS models, like the Xenoblade Chronicles remake that is being made for it.
I think it's a bit late for this now. I would have rather seen them put these features into a new handheld device and not divide the 3DS fan base like this, but that's just what I think.