Why would you need to upgrade? The PLAY:1 supports using either S1 or S2, both of which allow the use of Apple Music. If you’re looking to set up a stereo pair, you’d need another PLAY:1, which may be challenging as they’re no longer made, but you’d likely be able to find a used model out there. 

Ok, good news then I thought that Play speaker does not support Apple Music, or at least did not when I got it. Nevermind then and thank you!

Pretty much all Sonos devices support all services. Minor exceptions when you get to HD, I think, but certainly the PLAY:1 will be fine….

One more thing - does any Sonos speaker support directly streaming from Apple Music or all of them must play through Sonon player? Thanks

I think you may be getting your terminology confused. What the Play:1 does not support is Apple's Airplay wireless technology. That is totally different from Apple Music, which is a music streaming service, not a wireless protocol. 

You cannot use the Apple Music app to play through the Play:1. You would have to use the Apple Music integration within the Sonos app. (But see further comment below.)

You could use the Apple Music app to play through more recent Sonos speakers, which are Airplay compatible.  Airplay allows you to play any audio from an iPhone to compatible Sonos speakers 

If you buy an Airplay compatible Sonos speaker you can in fact group it with your Play:1 so that you could, after all, use the Apple Music app to play through the Play:1.

As Bruce pointed out, you cannot stereo pair different Sonos speakers, but you can group them to play together in sync.

Thank you for the explanation, this is exactly what I was looking for!