How to organize licensing of specific software?

Question

Programming

Hello, please tell me a service for creating a software subscription, or alternative ways to organize automatic licensing.
What I need:
1. Ability to work with a license key.
2. The key is issued to the user after payment, and is valid for a certain time (month, three, year).
3. The ability to use the trial version of the application for one month, once per user.
4. Ability to find out how many users are active at the moment.
5. Integration with any payment system (eg PayPall).
6. Ability to auto update software.
Interested in the cheapest way to implement, preferably an opensource solution, or a service that provides similar services for sane money.
~ Number of users < 1000.