I have tried to use this beta twice and had to downgrade to 16.3.2 due to it would either not work at all or was so buggy was unusable. First upgrade was from the 16.3.2 to 16.4. It went very had. It appeared to install all just fine. It rebooted and never connected to wifi again. I even factory reset and attempted to setup again as new but still would never connect to a wifi network. I finally gave up after a few hours and restored again to 16.3.2 and all came back as it should working. So I attempted once more to upgrade to 16.4. This time it at least completed and seemed to reboot and work properly. Did not last long. It would work and not work. At times saying it could not talk to the internet. Reboot and work for 15 minutes and again the same. In the end I gave up and went back to 16.3.2 and will leave it there till maybe the next drop and see what happens.
HomePod 16.4 beta
Installed on my Homepod mini and their it worked same as on the old 16.3.2. However on my Homepod Gen 2 it installed and seems to work fine however I cannot play any music from my Mac Mini M2 via Air on the Homepod. The selections works fine but no audio is played. When I try to play music from my iPhone 13 OIS 16.3.2 to the Homepod over Air it works fine
Stefan