https://www.bbc.co.uk/news/technology-51206604
TD;LR - Sonos will no longer be updating 1st Gen play 5's, CR200 and Bridge devices from May. While they still can be used (or 'trade up' with 30% credit for each legacy product), over time without software updates sonos stated that;
(https://blog.sonos.com/en-gb/end-of-software-updates-for-legacy-products/)
From my point of view I have 4 play 1's, I only added more devices recently to the original 1 I had for a few years, with the feeling that been tied into one eco system (ie the need to use the sonos app to stream anything to the speaker) was a bit of a risk. Now it seems that risk is potentially going to come into play. If the future rather than new speakers I think I might just look to stick with my Bluetooth HiFi system rather than expanding by sonos system any more.