One of our Nexus 9 tablets recently went into “eternal reboot” and we have had to do a factory reset/Android “recover from cloud” operation. Which was fine, except it doesn’t restore what was there, bur reinstalls the Apps from scratch.

So, suddenly, we have SONOS S1 app appearing instead of the v10.3 of the app that was there originally.

It is correct, as we only have the old S1 kit (9 older units), all at the same upgrade state as the V10.3 software.

BUT:

We also have six Nexus7 V2s as Sonos controllers distributed round the house. These had a final upgrade (August 2016) on Android 6.01, and could only run up to Sonos V10.3 (build 51166240). 

Yes, Sonos V10.3 eternally nags about “update available” and “upgrading our device” – which is not possible. So we have stayed at V10.3 as everything is still fine and we don’t want to buy 6 new tablets just for “upgrading” to Sonos S1, as the old ones work fine for all our other uses.

Of course, running S1 on the recovered tablet just brings up a load of spanners saying we need to “update”. If we don’t run the update the Sonos S1 app will not allow us to control any of the units.

Question:

• If we accept the "update my device" on the SONOS S1 app, what will happen to the other Nexus controllers which are running the v10.3 app ? 
  That is, will allowing the update destroy us using our six Nexus 7 V2s as our primary controllers?

We need a clear picture of what we might lose. The minimum function we need to retain in all our controllers is to be able to group and ungroup rooms, control volume, switch between playing sources/radio, and occasionally force a music library update.

This is important as we don't want to be forced to replace six tablets, as my understanding is once the Sonos devices are updated we CANNOT rollback to the previous configurations.