I think JetBrains model is best with thier IDE. You purchase, and get one year of updates, if you don't renew you get a perpetual license at whatever update level your update license ended at, and you can restart at anytime.
This avoids games about what is or is not a "new version" or shipping minor updates as versions or any of that nonsense, it's just updates generally.
This isn't true for JetBrains any more, and hasn't been for ~10 years. They run on what is essentially a pure subscription now, with the caveat that if you stop paying, you can continue to use a version of the software. However, it's not the version you're using at the end of your subscription period, it's the version from 1 year prior to that. So if you stop paying, you will probably have to downgrade. See: https://sales.jetbrains.com/hc/en-gb/articles/207240845-What....
This avoids games about what is or is not a "new version" or shipping minor updates as versions or any of that nonsense, it's just updates generally.