The rumour comes from VGLeaks, one of the more reliable sources of next-gen information in the build up to Sony's PS4 reveal last month.
According to the site, Square decided to halt FF Versus XIII PS3 development two years ago, when it switched the game to a PS4 exclusive and Sony came on board as a co-developer, "helping with assets among other tasks".
Either way, Im happy to hear its a PS4 Exclusive, dont offence, but I prefer Sony´s playstation over other consoles.
Just have a demo ready by the time the PS4 launches...