Hello,
Welcome to Microsoft Q&A!
If a user buys the paid version, if a new update is available he should not pay for the updates for a certain period or till a certain major version.
This is not possible for a paid app. If user purchased a paid app, then the user will own the app. The customer won't need to pay for the app again no matter how much time has passed or whether it has a major update.
What you want might be the Subscription add-on. You could use subscriptions to sell digital products in your app (such as app features or digital content) with automated recurring billing periods. When user paid for the add-on, he could use all the function for a period of time. After the subscription expires, the user will not be able to use the functions.(By checking the subscription add-on license in your app manually).
Thank you.
If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.