Plans for the Visits to Curriculum

Is there a plan for when the future volumes of the Visits to curriculum will be available and how that will affect the history modules? Which history volumes already include the Visits to books?

I like to buy ahead and preview future volumes, but don’t want to buy editions that are going to be updated before I’m ready to use them.

I’m thinking of just buying the current volumes and using them as written or scap the entire geography curriculum and using the Mark Twain workbooks I already have. I prefer not to jump around, and want to use one geography publisher for all 6 years. I’m content with Visits to Africa, but I like the Mark Twain workbooks just as well. They are quite different, but each curriculum has it’s strengths and weaknesses and focus topics.