Ok, picky.  S1 Compatible only an S1/S2 Compatible.  And reasons for having S2 is not the issue - it’s how they implemented it. 

It's not beimg picky. It is precisely because there are devices that could go in either an S1 or S2 system that it is better to have a clear separation of the units in the two systems. 

The fact that you think it is being picky shows you have missed the point. 

So there is no way to downgrade a system once every unit has been converted over to S2? My setup of 4 Play:1’s has been working perfectly for years now, but after the S2 upgrade they are basically useless to me. I am getting frequent drops on the systems and we only have 1 device that can run the S2 app. They were upgraded on accident, and up until now I loved the system, never needed to come here for support. Not a power user but a user that has gone from very satisfied to debating tossing the whole system on ebay.

From what I've read here there seems to be no difference between S1 and S2 from a wifi- standpoint, unless you where dependent on a Bridge, that is defunct under S2, but could be replaced by a Boost.

If by “we only have 1 device that can run the S2 app” you mean the phone you are using the app on, I think the requirements for the S1 and the S2 app are the same, so you also could run the S1 app on this device only.

From your post I gather you have wifi problems. Have you called Sonos to let them try and help you with this?

Thank you for your reply, unfortunately the S2 app does have different requirements - it is a 64 bit app on iOS and won’t run on older iPads or iPhones and unfortunately the rest of our home automation stuff is setup on older hardware that I don’t want to replace right now. My wife has a new iphone and didn’t understand that clicking the insistent upgrade button in the S1 app would make it so our Sonos system no longer worked with anything else.

Luckily we don’t have that large an investment in sonos stuff so far, the cost of replacing the other components would simply be more than replacing the sonos.

If I were to get an older device on ebay, could I setup a new S1 network and then reset all my devices onto that?

Should work, I bought a ZP90 just so it would fail compatibility check for S2 and would allow a means to go back to S1 if necessary.

Luckily with it on my system it seems to have got rid of the incessant S2 upgrade banner..

To control your Sonos stuff on old iOS devices, get SonoPad/SonoPhone from the App Store, It runs on ancient devices.

I think this is insane! 

Wy should i not to be able to play the new IKEA frame on a S1 system!!!

i dont care about the socalled Extended functionallity. 
i dont need to talk to the loudspeakers….

i just want to play music in a group, without pulling wires!!

That a new IKEA frame is not possible to talk to S1, is only because of there interest in earning money for theiere owners.

Sonos should be stopped by a law. Enviromental polution is not considered…

question is what system do I switch to?

replacing amp’s is insane expencive… and in another 10 years….. Sonos S3…

and here er go again…

Sonos earned theire trust from theire consumers, but now…. Not any more….

So you expect a piece of software which was last updated in 2020 to recognize a device which is  released in 2021?  

Yes, 

bits and bytes has not changed! It is only the performance and processing power etc..

So you think that a newer stronger processor could not handle to «talk a earlyer» language/OS?

especially basic sound(!)

It is only  SW related. 

Of course newer standards in BLE/Wifi etc evolves. But making compabillty is ONLY a question of making money!! Nothing else.

if you look at the electrical industry, a «smart building» system was developed in the 90’ by the germans.(EIB) This system is bigger than ever, and even though memory and processord has evolved. (EIB/KNX) You can still use a sensor from the 90, but it has limitations regarding (Application program and how many connections)

The newer ingeering software is back-compatible.

So for sound listener who just wants to use it to listen to music, it should not be a problem.

Airplay, Siri, surround, yes I can understand that you need S2 - performance!

So Sonos, you have lost a fan……..

If anyone ask me now, I will not recomend Sonos anymore. Because of theire expencive products and that you must upgrade in the future.

S1 needs to recognize individual hardware units in order to sync up with them and play.  New S2 units aren't recognized by S1 because they didn't exist on S1.  New S2 units cannot be added to S1 because S1 will then be too big to run on S1 only devices.

How's that for "bits and bytes"?

Also, why would Sonos essentially give up on new sales to S1 users if they didn't have to?  That's silly.

So how did they manage (and still) to include the other symfonisk speakers from IKEA into the S1?

they have airplay.

it’s all about the date… (!)

Just a milstone for dropping out new supported devices to S1…

All about the cash, decided by the men in black suits…

Sono is pure crap since S2. I used to be so happy with my S1 system and showed it off to anyone who came over.

I cant even play a song anymore with drops or the song randomly changing halfway though on S2.
Same equipment more excuses about wifi interference but its quite funny how Samsung multiroom dont suffer… 
Im about to throw all these Sonos bricks in a pillow case and find a overpass…. 

Your issues sure seem like network issues of some type to me. I never had issues with either S1, nor do I have issues with S2. It’s challenging, certainly, but any network device such as Sonos is only as good as the network on which it sits. And since Sonos does so much cross talk between devices, in order to main tips in sync, it does have slight lumpy more stringent needs than many other network devices, but not so much so.

There’s not enough information in your post to help identify which particular network issue you’re experiencing. If you’re looking just to complain, then you’ve done so. If you’d like help from this community, posting additional details about your system would help us help you. 
 

However, since Sonos works so well for the majority of folks, if you’re unwilling to invest the modicum of effort, I’d suggest reselling your equipment to someone who’s willing to look at the issues. Sonos retains a significant re-sale value. May not be as satisfying as throwing them off an overpass, but your wallet would likely thank you.

The operative phrase here is “existing Sonos product running S1 is required”. I was pulling out my hair trying to get my brother’s Play 1’s downgraded after he made mistake of upgrading to S2 and discovered he could no longer control his Play 5 Gen 1. I had disconnected everything but couldn’t get the factory resets on the Play 1s to take - S1 kept informing me that they were not compatible with S1 and required S2. Then it hit me that I had the Play 5 disconnected and should start rebuilding the system with it. I connected it to router (but I’m not sure that was necessary) and rebuilt the system. After that, Play 1’s connected with no problem. Only remaining scary problem (after fighting this for hours) was the last request from setup menu to “upgrade” - did that mean upgrade S1 or upgrade to S2? I took the plunge and accepted upgrade and was relieved that it did not upgrade to S2. All is good now.

I’m sorry to complain BUT I’m going to.

I had 6 S1’s and 1 Play:5 running Controller 1, everything was fine we loved our whole house Sonos system. Then the upgrade notice came and my wife pressed it. S1’s are fine bricked the Play:5. I’ve tried going back to Controller 1 with partial success, still can’t get my play:5 to work. $500 shot to hell.

wouldn’t recommend Sonos ever. I have $2000 worth of equipment. I feel they owe me a Play:5, they made a dumb decision, if they thought I’d buy more compatible equipment, they’re nuts. Who knows when they might do this again. Bad marketing or dumb engineers, 3rd parties have figured out how to make S1 & S2 work with one app…..

Did you remove the Play:5 through the App when upgrading?, this will have factory reset it.

You will have lost your account on the Play:5 and everything will have moved over to S2.

I would be tempted to wire the Play:5 to your router and try to set up an S1 system with the S1 app from scratch, turn off ALL your other speakers first.

You may need to create another Sonos account, but that will just be temporary until you get everything back on S1.

I'm still on S1, still works exactly as I want and see no need to go to S2.

It's amazing how any user can allow upgrading, in my opinion there should be a Master User and only they can allow these upgrades.

I put a speaker on S2 for my Daughter purely so she didn't accidentally upgrade our whole house system.

Like the rest of us, probably with Sonos for failing to adequately support S1, providing instructions for a downgrade that doesn’t work, for installing upgrades without notice, and for providing erroneous information.  Does that help? 

Exactly what happened to my system except for the wife part.  While installing a new S2 device, all my units were upgraded to S2 except my Play5.  And the downgrade does not work.  So now I’m in limbo.  Really mad at Sonos. 

I have also upgraded my one SL to S2 after my router went down. This SL was configured to a S1 controller and was functioning well together with the other S1 speakers. Now I cannot downgrade it to S1 again. It plays well on the S2 controller but when I try to downgrade it the S2 controller cannot find the one SL. Any Ideas what I can do?

Once a Sonos OneSL is running on S2 there is no way to downgrade back to S1. 
It just still works for Sonos One (without SL).