I see that 6.5 and 6.6 came out in October only 2 or 3 weeks apart. So can you update as many times as you want until version 7 comes out or is it only for 1 year until you have to pay the upgrade fee?
What is considered a version update?
You get 1 year from payment for all updates for that year (365 days), so its not dependent on major/minor version numbers at all.