There is a forth in the Bobiverse series called Heaven's River. Currently only available in audiobook. Other formats later this month by the looks of it. https

There is a forth in the Bobiverse series called Heaven's River. Currently only available in audiobook. Other formats later this month by the looks of it. https://www.goodreads.com/book/show/42950440-heaven-s-river https://www.goodreads.com/book/show/42950440-heaven-s-river