Resetting is not going to solve that problem.  A reset just clears out the data, it’s not going to affect the underlying software, your devices will still be running S2.

Sonos support is not based on the hardware version of your phone, it’s based on the software.

https://support.sonos.com/en-us/article/sonos-app-requirements

I would highly recommend that you don’t downgrade your speaker firmware to be compatible with your current iphone software.  Eventually, your setup will not be supported on S1 either.  It makes a lot more sense to upgrade your phone to something that is supported by Sonos and Apple.

@poldings maybe you can borrow a device to get your whole s2 system online? Then convert to s1. Don’t forget to turn off auto updates in the app and on your phone or as @melvimbe points out you may find your phone unsupported in s1 eventually 

https://support.apple.com/en-ca/HT202180

Thanks for your feedback.

I appreciate now that the speakers with Sonos 2 software on them will still have Sonos 2 software on them even after a complete restart. In which case that is indeed not a solution for me.

In this house we have 3 phones and none of them can use the latest version of the Sonos 2 software.

- iPhone 6 running IOS 15.8.2
- iPhone 7 running IOS 15.8.2
- Samsung Galaxy S7 running Android 7.0

None of the phones can upgrade to a higher operating system.

I also have a MacBookPRO with Sonos on, but that does not seem to allow me access to manage the system settings.

Is the final consensus that I need to invest in a new phone just to connect my Sonos speaker to my Sonos network?

I admit that’s one way to look at the situation.

Alternatively, you could consider the security risks for any and all outdated apps and operating systems on your old hardware, and weigh up the cost of updating your gear with the potential cost in the event of a security breach. 

I am not speaking for anyone else, but I would update your phones because those operating systems are no longer supported by Apple, Samsung, and Google, and therefore no longer getting an security related patches.  They are a vulnerability on your network.  Getting your Sonos up and running is secondary.

If you want to run s2 yes. 
 

If you want to go with s1 have you tried following the directions at the link below? I wonder if you log out of the s2 app and tap more options instead of set up or join if you can get to the downgrade product to s1 screen.  Disclaimer I’ve never done this so this might be bad advice  

https://support.sonos.com/en-ca/article/downgrade-a-sonos-product-from-s2-to-s1

Edit: @melvimbe makes a good point about security.  But IIRC your iphone 7 still receive security updates from Apple and I believe S1 gets security updates from Sonos so you have a bit of time with this device. 

If your iPhone 6 is actually a 6s (which it must be if it’s running iOS 15.x) it is still getting security updates  

Depending on the SONOS model, it may not be possible to downgrade to S1.

I have several outdated devices, Apple and Android and last I looked (couple months) they still worked just fine for playing music on my Sonos. Never paid attention to just what they won’t do but I’d expect add/remove speakers or run updates. Doesn’t matter as I have newer devices that will do that.

I’d either get a newer device to do anything you need to do, that your old gear won’t or have a friend with a newer device come over for a beer and update session.

According to your profile, you have Sonos One SLs. They cannot be downgraded to S1