Microsoft has started rolling a major update for the Xbox One, which brings with it two new features, the New Xbox One Experience, which is based on Windows 10, and Xbox One Backward Compatibility. The New Xbox One Experience brings with it a new Dashboard and a new Guide. The focus here is on making everything faster, not just performance wise but more importantly, in reducing the number of steps involved in doing things. The guide helps out in this a lot. The guide is like a hub for all your friends, parties, messages, notifications, settings, and apps. The guide slides over from the left as an overlay on the Dashboard, in an app or even during a game, so you are never far away from important things. The other important thing is Xbox One Backward Compatibility. Now Xbox One users will be able to play over a hundred Xbox 360 games on their console, with more coming in the future. The Xbox 360 titles can be downloaded from the store if you had purchased them digitally in the past. If you have them on a disc, you have to enter the disc into the Xbox One, at which point the game will be downloaded from the store, with the disc acting as sort of a DRM. You can play multiplayer within these games with Xbox 360 owners and also have access to new Xbox One features, such as screenshots, in-home streaming, and Game DVR. The update is now rolling out and you can read more about it in the link...
Source: http://www.gsmarena.com/xbox_one_update_brings_new_ui_backwards_compatibility-news-14985.php