First, you’ll need to at the very least, dump the BRIDGE in order to use S2. You could get a BOOST to replace it, or simply wire one of your PLAY:3s instead, to the router. Note, however, that just upgrading from S1 to S2 doesn’t get you AirPlay 2. That requires a specific hardware piece that didn’t exist when they were manufacturing the PLAY:3. I have several PLAY:3s in my system, which runs S2, but they aren’t able to be AirPlay 2 targets. I usually just “target” a Sonos One, and then group the PLAY:3s with that to get the AirPlay 2 signal on all those speakers. 

Similarly, there are CONNECT:AMPs that don’t have the ability to work with S2, and also don’t have the necessary hardware to be an AirPlay 2 target. 

You may want to check your system on your account at www.Sonos.com which should give you details, and offer you upgrade pricing, depending on if the upgrade has been “consumed” already or not. 

Certainly a new Sonos Amp does have the capability of being a AirPlay 2 target, and can run on S2. 

While the three Sonos Fives would be a significant sound upgrade, I’d really be tempted in your case just to get a Sonos One and then do the grouping thing. 

Thanks a lot for your advice, Bruce. I hadn’t thought of that solution (buying a Sonos One). However, I'm wondering how (if) the grouping thing will work ideally when I want to use the speakers in two different rooms? ( I have two play:3’s in my living room and, one in my kitchen)

If targeting the Sonos one, and grouping it with the Play:3’s, I assume I will always have to have the Sonos One turned on (i.e. to produce sound)? For example: if the Sonos One is placed in my living room, I assume I’m not able to only turn on my kitchen speaker since it will be dependent of the Sonos One, which is placed in the living room? Am I right? (and does it makes sense?)

/Louise. 

The Sonos One would need to be the ‘target” of the AirPlay 2, but the volume could be zero on it, and the playback then occurring on either (or both) of the two “rooms” you’ve decided to “group” with that Sonos One. Once the signal is inside Sonos, you can effectively send it anywhere in the Sonos system. 

And, come to think of it, this is actually what I sometimes do in my bedroom, which has a Sonos One, and a pair of PLAY:3s. I often listen to baseball games, and occasionally send the AirPlay 2 signal to the Sonos One, have the volume at zero, and play the grouped pair of PLAY:3s, which are situated to give me stereo. Important in a bedroom (OK, maybe not, but that’s the way I go) but the PLAY:3s are a good playback device for that grouped signal. 

Edit: Yes, I probably have too many Sonos lying about :)