In the latest and least complicated news from Mircosoft regarding the Xbox One, Microsoft Game Studios VP, Phil Spencer advised gamers to keep hold of their Xbox 360s if they want to play XBLA games. Why? Because,

The box is not backward compatible and we think for somebody who invests in a large digital library that you want to keep your [Xbox 360].

In laymen's terms, the systems aren't the same architecturally and something had to go.

As I previously reported last week, Microsoft is planning to sell the the Xbox 360 along Xbox One as one happy family making it possible to access your account on both systems; putting to rest the rumors of needing to create a separate account.

Spender continued to say,

You don't have a separate identity on Xbox One or [Xbox 360]; it's the same, you are you. My friend's network is the same on both boxes, my achievements are the same. So we think that service component is an important component to keep constant across both devices.

On the plus side, you can still interact with those on your friend list and achievements will remain unchanging between the two systems. In addition, Microsoft is planning a big reveal for the Xbox 360 at this year's E3 conference, so all is not lost.