That does work for Android. Unfortunately all decks are lost and the only deck you end up with is the last one loaded. Couldn't save a deck but you can edit. I hope they give us a true offline...

I'll be honest and saying I don't see any offline mode for the current version anywhere in the app for Android. Maybe I missed is it somewhere. It's no in the login menu or anything.

I would be over joyed if we got an offline version so we could keep what we have gotten over the years and still be able to play even if it's the campaign. But that's just me.