Same problem 

Same here. Device is now useless.

Is there an eta as when the new app will have the option to have the volume out set to Fixed and pass through to work with "work with Sonos" compatible components as it was available with previous version of the app?

Sonos has a page where they list coming features and this is not on the list. Here’s the page 

https://support.sonos.com/en-ca/article/the-new-sonos-app-and-future-feature-updates

As luck would have it I had an android phone with the previous working Sonos app, I was able to setup the Line-out parameter for the Port to Pass-Through.  Connected the Line-out from the Port to my amplifier, I can now use my wired speakers!

it is a shame the new Sonos app renders our Sonos investment almost useless.  If I hadn’t  had this old android phone I would have had to wait who knows how long to configure my Sonos Port with the Pass-Through parameter!

New app update restored the line out functionality Just saw it today