Having used and owned Sonos devices, this doesn't surprise me at all. The devices expect to work together in complex ways. Expecting new ones to correctly work

Having used and owned Sonos devices, this doesn't surprise me at all. The devices expect to work together in complex ways. Expecting new ones to correctly work together with old ones over the same network can be expected to entail pretty much all the work of supporting the old devices. New devices are now constrained by the networking hardware and protocols of the old ones... forever. Which is the whole thing Sonos is clearly trying to get away from. Supporting legacy devices forever is clearly untenable. With that said, I do see another angle they could have pursued. They could have led with the network segregation approach, making it clear that the legacy devices will still work perfectly with one another on their own network. Sonos could also have said that legacy devices may stop working as expected without warning after any future update that applies to current devices only. This strikes me as likely to work great until it comes down and then it blows up catastrophically when the update lands. Those are the best options I can see, but my vision is of course quite limited. Perhaps you have better ideas!