I ran into the same thing and had to go to the new app.
However, it now seems to have a new problem. With the new app on my phone, it runs a background task to alert me to new posts in subscribed threads. When I go to read my threads later on my PC, I find that they are all marked read, so I can't tell what's new and what's not. Apparently, every time it checks for new posts, it is marking them as read.
It seems that the app assumes I'll only be using my phone to access talkbass and will go read the threads as soon as it alerts me.
Is there a way to disable this "feature"?