My understanding is that this is possible because at some point, the private keys for the airplay encryption were found. Alas airplay 2 cannot be supported unless the same thing happens, which is a shame.
Is it quality?
- Airplay doesn't offer multi-room audio; AirPlay 2 does
- AirPlay lets you stream from any Apple device to your speakers or TV
- AirPlay 2 lets you play from speakers over Wi-Fi, and it'll stay in sync
- AirPlay 2 lets play different songs in different rooms with multiple HomePods
If memory serves, the original AirPlay had much simpler goals. Stream music from a single computer to a speaker over a local network. So it has concessions like a constant 2 second lag, which happens if you press pause/play. I vaguely remember other weird restrictions when playing with it in the past (like one device at a time had to control a speaker).
AirPlay2 is a lot more complex adding the features mentioned above and better handling the use-cases original AirPlay grew into.
https://www.pocket-lint.com/speakers/news/apple/144646-apple...
This makes play/pause etc instant (rather than waiting for the 3 second buffer to run out) and makes it much easier to do multi-speaker audio as they're all listening to the same media stream.