One can implement the pricing model used by Sketch, and do it via In-App purchases. Pay and get updates for a year. After that no new features work in your copy

One can implement the pricing model used by Sketch, and do it via In-App purchases. Pay and get updates for a year. After that no new features work in your copy or any updates to your copy, unless you pay again. https://www.sketchapp.com/pricing/ https://www.sketchapp.com/pricing/