To be pedantic, “S2 rollback” was never officially alive, was it?

I don’t recall there ever being an official Sonos-approved method of going back to a previous version - neither of the app nor of the Sonos devices themselves.

You don’t say what version of the app you have, nor what version of firmware. As far as I can tell, if you allow the system to upgraded to the latest firmware version, that may close out any future option to “unofficially roll back”.

Seems like if one of the speakers get updated, one cannot use the old app anymore..

And there apparently isn't any way of downgrading the firmware to an older version.

Anyone know a hacky way to force older firmware unto the speakers?

Hasn’t it always been the case that if one component is updated then all speakers and controllers have to be updated to remain in sync and compatible? 
 

And I do remember a year or more back when Sonos issued a release with a major bug that took several weeks to fix. No roll-back was available then, either. 

I suppose it has.. There should be a way to select which FW you’d like to install on your equipment tho.. Especially when new FW (and other updates) ruin the usability of the products..