Easily see which Achievements you are closest to, and quickly launch the game to obtain them. There are sort filters that allow you to prioritize next Achievements by closest, most common, rarest, most common rare, and highest Gamerscore.
The second change is to Xbox Live's Game Hubs, to the Guide menu, with "Small Game Hubs" offering snappy features. This also allows you to easily see which Achievements are almost achieved alongside links to quick load those games.
The update is rolling out today for folks who are in the Alpha ring of the Xbox Insider program, and there are further experimental updates coming as well. Will be able to access content for games you've played recently from a Game Hub without ever having to leave the action. Via Mini Game Hubs, you'll be able to see friends now playing, upcoming achievements, Looking for Group posts and other info.
A "Do Not Disturb" online status has been added, which will suppress notifications and let players avoid distractions and focus entirely on their game. This is a handy feature for those that don't want interruptions while focusing on their game.
The community feed will be tweaked so the most recent comments will be displayed first, and players will also be able to see who has liked their comments.
Xbox One's new Do Not Disturb mode is a lot like Windows 10's Quiet Hours feature. More granularity for auto-shutdown timing is en route as well, with options that will turn the console off after two, three, four and five hours. Since the new Xbox Avatars won't arrive until early 2018, it looks like Microsoft may be bringing new surprises with Xbox Achievements too.