Do you also have to purchase each new update which comes out?
Not with LogTen Mobile.
When I started with LogTen Pro it was version 3.x, and upgraded to ver 4 soon after. My upgrade to ver 4 was free, and updates to both ver 3, 4 & 5 also free.
When I upgraded to ver 5, I can't remember if it was free or discounted to existing customers.