The normal way should work. Just go in to the controller, and choose ‘check for updates’.

If that fails, if the controller doesn’t have access to a build that allows updating, you have to call Sonos Support directly to discuss it. They’ll pull a special update build for you, and give you access to it temporarily.

You can also try connecting via an Ethernet cable.  There's a chance it will update that way if wifi is too out of date.  If not, the call to support is the only route.

Where are my speakers!?!?!?!

jgatie:

Thank you for the advice! The ethernet connection worked!

I have a similar situation, tried the ethernet connection fix, but no good. With a 65 minute wait to talk to someone, I must say, it’s not worth my time. 

@Uman :

I had to plug my speakers in, then open the app. If I had the app open before I plugged the speaker in, it wouldn’t work. Also, the actual fix took about twenty minutes for both speakers to update (I did them one at a time), rather that the “two to three minute wait” that the app said it would take.