WP Travel Pro comes with the initial 1 year of Subscription i.e. you can download the updates till 1 year of purchase date. But after one year, you will need to renew your subscription in order to continue downloading updates.
For the renewing process, please once refer link.
But this subscription has nothing to do with the usages of the plugin to your site. You can use it in your site as long as you want it without renewing your subscription. The only thing is you don’t get the latest update of the plugin.
If you have any queries, please submit it to our contact page.