What happens if I don’t renew the annual fee for PRO?

WP Travel Pro plugin comes with an initial 1 year of Subscription i.e. you can download the updates till 1 year of the purchase date. But after one year, you will need to renew your subscription to continue downloading updates. But this subscription has nothing to do with the usage of the plugin on your site. You can use it on 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.