"I don't know where we are with Microsoft right now so I can't really comment on what that contract looks like," he said. "The point is we are developing for Xbox [One] and PS4 simultaneously. We hit those major platforms and then our goal as a development team is to make them run."
According to Mayberry, "it makes more sense" to develop both versions at once. "We've already done it with the 360 and PS3, so that team knows how to develop at the same time for both of those platforms," he explained. "That's just what we do. And then Blizzard and Microsoft can work out whatever they work out." If I were Microsoft, I'd be pushing for that Xbox One port.
Diablo 3 is in development for Xbox One [Videogamer]