Earlier quoted context omitted.
how do you feel about licensing where you pay once, get the software, and have access to updates for one year? if you want future updates, you pay for another year of updates (discounted, of course, for loyalty). or is it more compelling to just have one clean, flat, lifetime rate?
I think the best way is you buy a software, and that version is supported "forever". The developer then creates version n+1. The old version is kept supported, but new features go only into the new version, which you can optionally buy again.
You can pay to unlock advanced features and keep them and any new features added in a year, after that any new features are paywalled for another unlock, and another +12 months, perpetually.