Microsoft is rolling out an update to Groove Music for Windows Insiders on all rings of the program. In fact, users on the Fast, Slow, and Production preview rings of the Insider program for both Windows 10 and Windows 10 Mobile will see a boost up to build number 3.6.2205.0 — the first time in a long time all three have been updated to the same build. (We're actually guessing on Slow, but can confirm Release Preview and Fast, at least).
Unfortunately, there doesn't look to be anything big in the way of features with this update. However, we have noticed a significant boost to performance after updating. Your experience may vary, of course. By the looks of it, Microsoft is putting the final touches on Groove for the forthcoming Anniversary Update, so there will probably be just fine tuning from here until July.
In any case, if you're on the Windows Insider program, you should be able to pull down the latest update to Groove Music now. For those not in the Insider, you'll remain on build 3.6.2096 for the time being.
If you happen to spot anything notable that we missed, be sure to give us a shout in the comments!