It seems like the best solution is to have monthly subscription model. That's what most companies are doing. Personally, as a customer, I like the idea of payi

It seems like the best solution is to have monthly subscription model. That's what most companies are doing. Personally, as a customer, I like the idea of paying for an update. Let's consider Adobe CC subscription. Currently it's standard monthly subscription, if you don't pay, you don't have access to it. I would prefer to pay only if I want new features and security updates. If I decide not to have them I could stay of the last version that I updated to. Of course to make sure that you earn enough you should have to have a limit of minimum 1 year subscription payed monthly, so nobody would scam you by buying one monthly subscription once a year. This of course changes is cloud services are involved (storage, streaming, etc.). For those you need monthly subscription to be on)