Update: Polygon Source Info in OP - Kotaku: Xbox Slim This Year, More Powerful Xbox One In 2017, Future Titles to Release on XB/PC, Iterative boxes from now on

[GribbleGrunger]

Aeolus451 said:
I doubt that any of it is true. Kotaku isn't really trustworthy. Phil has said they're not working on an upgraded console before.

This reply doesn't exactly sound like he's denying it: