Generally this is primarily a graphical and user-interface overhaul. We do plan to have some new content and some new puzzles, but we're trying to be very careful not to disrupt the story as it currently stands.
We're not adding any new people to the main family tree, for example, and I don't have the bandwidth to create an entirely new family tree like I would if this were a sequel.
Instead, I'm working on ways to include bonus content to investigate into and solve that fits nicely into the story I've created.