As detailed on Xbox Wire, the update is available today for Xbox Insider Alpha Ring members.
Xbox One X and S models will now also support 1440p output, a popular resolution used on PC, bridging the gap between HD and 4K screens.
On the smaller scale, background music and system audio can now be more effectively balanced, Edge browser navigation has been optimised for controller, Xbox Club owners can filter invites more efficiently, activity feeds have been improved and Tournaments are now open to users who aren't part of a Club.
A portion of the Xbox Insider audience will also get access to an "experimental" feature, allowing you to browse a menu made up solely of Games With Gold offerings you've redeemed, and installing them with two button presses.
No timing's given for when the update will be made available to all, although it's usually around a month after the Alpha Ring sees it.