If you're an Xbox Insider on the Preview Alpha ring, there's a new version 2008 preview on its way to you today. But unlike the vast majority of Xbox Insider builds, build 19041.4067 actually contains a bunch of new features.
First up is a faster and better Microsoft Store. This was announced earlier this week, and was promised for Xbox Insiders. Not only is it meant to be faster, but it should be easier to use and more secure. Right now, it's only available to some Insiders, and only in the U.S., UK, Canada (English), and Germany.
Also available to a random subset of users is a new Game Activity tab, which replaces the Achievements tab. The idea is to focus on the game you're playing or last played, and Achievements stay at the top, although some things have been reworked. There's a toggle to turn the Achievement Tracker on or off, you can see next Achievements, and more.
Also in the Game Activity tab, you'll be able to see which of your friends are or have played the game that you're playing, and you'll see LFG posts for that game. You'll be able to see the official Club, and suggested events.
Finally, there's a new Happening Now feature, which may show up in the People area of the Guide, at the top of your Friends list, or not at all. If you haven't noticed a theme yet, there's a lot of A/B testing going on. This will let you find friends that are in joinable games and such.
The new build is rolling out now, and will roll out to the general public this month.