Hello, complicated answer it seems.
A piece of the answer here: https://support.sonos.com/s...
So from May 2020 some hardware will no longer be supported by their software updates, depends on the date of manufacture (not the type of product).

My personal experience is very recent:
I just received a Sonos Connect as a replacement (Warranty). The new one received will not be supported, the one sent back (bought December 2018) would have still been supported after May 2020.....Bref it's not joy.
My Sonos Play 5 and two Sonos Play 1s (bought December 2018) will still be supported.

So most likely a purchase now will be supported, but given my problem above this is not guaranteed.