If you're on the Preview Alpha ring of the Xbox Insider Program, it's once again time to check for updates, as build 15063.2009, or rs2_release_xbox_1704.170328-2321, is now available. It's another preview of version 1704, which the version number indicates will be finalized sometime next month.
The release notes don't point out any new front-facing features; however, when Brad Rossetti announced the build on Twitter, he said to check out the new LFG (Looking for Group) features. Indeed, Microsoft has said that not all of the planned features are currently in preview.
They did, however, list a single thing that got fixed:
Fixed an issue with automatic sign-in where the console failed to recognize a signed-in user after powering on.
Interestingly, Insiders on the Preview Beta ring got the previous build tonight, which was 15063.2006, and this isn't listed as a known issue in those release notes. In fact, the known issues for this build are exactly the same:
Settings - Display & sound
The Audio output page is under construction and some of the new settings are not yet functional. New support is planned for Dolby Atmos for home theater, Dolby Atmos for headphones, and more in upcoming builds. An announcement will be made when these new features are ready to try out; enabling these settings now will have no effect.
The Wireless Display app fails to launch and immediately crashes to Home.
Version 1704 will follow the Creators Update for the Xbox One and One S, which was released on Wednesday. As mentioned above, the version number implies that it should be finalized in April, so those on Preview Ring 3 should see a build soon enough.