There’s this thread where Josh has been collecting feedback and suggestions for his next course. I’m not sure whether he’s actively working on it or it’s something for the future, but as far as I know he hasn’t shared any specifics yet (especially not a release date).
As for what you can do after the course, you can take a look at the BassBuzz video guide thread and go through all of Josh’s YouTube videos. Or if you are doing the course right now, you might as well watch the relevant ones after each module.
Many people also plan on doing the course a second time. I definitely think that would be useful for me as well, but haven’t been able to convince myself to dedicate those 100 or so hours to the course again.
Personally, I spent a month or two learning songs after B2B, and then started going through a bunch of books with all kinds of exercises. I’m now working on improving my groove (especially 16th notes), finger dexterity, sight reading, some more music theory… So basically everything. (Except joining a band. That’s not for me.) And I am nowhere near advanced, so I keep coming back to the forum to ask stupid questions. and share accomplishments, if there are any 