Microsoft has confirmed that you will not be able to play your Xbox 360 games on your Xbox One, thanks to significant hardware changes under the hood.
Xbox One hardware is not compatible with Xbox 360 games. We designed Xbox One to play an entirely new generation of games—games that are architected to take full advantage of state-of-the-art processors and the infinite power of the cloud.
This doesn’t just mean that your collection of discs won’t work. Your Xbox Live Arcade titles are being decommissioned as well, again due to that new core architecture. Xbox 360 games were created for a PowerPC architecture known as Xenon – the new Xbox One uses an x86 CPU instead. More grunty, less compatible.
The press conference confirmed that new Xbox 360 titles would be on show at E3 next month, and while the console will eventually be phased out, Microsoft plans to continue its support for the Xbox 360 with “a pipeline of new games and new apps” stretching to the future.