Downgrade Sonos Port from S2 to S1

UPDATE - successfully downgraded to S1 - it was necessary to turn off WiFi during the process just before the App tried to call home for the update. Then it skipped the update request and the process could be completed after switching WiFi back on again afterwards. Another system back on S1 and it just works fine! Thanks for making my life complicated SONOS!

Has anyone recently had any success with downloading the old S2 app. ? Ive tried it on various devices from apkmirror and nothing seems to work as it just tells me to sign in and then the app goes immediately to request an auto update to s2. Ive installed the 16.1 S2 app on an an old samsung phine running android 7.0, an I phone 4, and iPad mini gen 1 - all with the same results - it just forces you to update the app. Does anyone have any suggestions - I;ve got 2 subs that auto updated to s2 which I need to downgrade to s1 again - and am completely stuck

I have just successfully downgraded the last of 4 homes from S2 back to S1, for anybody interested here is what you need to do:

1. You need an iOS device that can run iOS 15 / iPadOS 15 as the final version (iPhone 6s or 6s plus, iPhone 7 or 7 plus, iPhone SE (1st gen), iPad Air 2 or iPad mini 4.
2. Make sure it is updated to the latest version (iOS 15.8.2)
3. Remove the Sonos App if installed. Download it again, on a device in the list above it will only download the old gold 16.1 version since they do not support any newer versions.
4. Factory reset your S1 compatible player / component (for a full compatibility list see Sonos support document).
5. Use the S2 16.1 App to initiate the downgrade process (see Sonos support document for instructions)
6. On your regular controller install the Sonos S1 Controller App.
7. I recommend creating a new Sonos account to keep the two systems separate during the process.
8. Create a new system starting with the first factory reset player using the S1 App with the new Sonos account. I found some players require to be connected via LAN to the router / mesh for the registration.
9. Repeat with the rest of your equipment and then add your services and music library (even SMB V1 will work).
10. Delete the new Sonos CrApp, disable automatic firmware updates in the Sonos S1 App and disable automatic update of the S1  Controller App in the iOS App Store settings.
11. Now simply enjoy your music again like before and  no matter if Sonos goes belly up or not you can continue to do so.

If I didn’t have a One SL in a pair with a One in my system I think I’d be doing this… I was considering getting a Sub-mini to go with them, but not now. I might just buy a One on eBay to replace the One SL and downgrade. This complete app screw up is going to cost Sonos in new revenue and customers. I wonder how long it will be before they just make going back to S1 impossible. 

Since it looks like the downgrade option has dropped off the agenda (see the CEO’s statement) I do suspect they will make it impossible in the future (or just more players will join the Sonos One SL where they already prevent the downgrade) so I strongly recommend downgrading everything that can be downgraded now using the process outlined above before they close this loophole. I just left the Sonos One SL’s (the only non S1 compatible devices I have) on S2 and listed them for sale on a local site. 

@Loyal customer for 12 years 

As some one that never left S1 and continued therefore to have no disturbance in the Sonos experience that many have suffered, I am only curious about this last assertion you have made under 3 above.

My understanding is that the use of even S1 involves Sonos servers in some way. If that is the case, 3 cannot be correct where it relates to a post Sonos having gone belly up time. 

Question therefore of interest to many here that are on S1 - which of the two are correct understandings of how Sonos systems work in S1?

Also very interested in this, my assumption was that as long as no changes to the setup are made / required I can continue to access and play my music library (this currently works as long as WiFi works even without internet connection) as well as Airplay to the Players that support this even if Sonos doesn’t exist anymore and their servers are down. But again, that is just my assumption based on my very limited technical knowledge.

I too would love this to be the case, but….!

Actually I worry less about Sonos going belly up, they will be bought before that happens. The worry is if Sonos or a successor pulls the plug on whatever is needed for the S1 controlled environment to work, because of commercial reasons. 

The S2 to S1 downgrade tool has been added in today’s app update.