Totally agree, just an incredible update. Also have stereo pair of old HomePods and am now avidly gulping down listens of my jazz and classical favourites that are in Dolby and/or lossless: astounding.
Can you do a test for me? (if not too much inconvenient). Can you play a lossless track -not Atmos, because the difference is evident- then disable lossless in the home app settings, play the same track and then re-enable lossless when you´re done?.
Just to know if you can tell the difference between lossy and lossless on your Homepods. Thanks in advance.
PS: I also have an stereo pair of OG Homepods, and a Mini in the kitchen. I have updated them all to 15.1 but wouldn´t be able to test the sound until tomorrow.