Every time you launch Sync, you will be informed about any lack of active subscription with the following message:

If you don’t have an active subscription, you will still be able to use all features of Sync except Synchronization.

The option "Synchronize Selected" and all the tools under the "Synchronization" panel will be deactivated including Scheduler, which will not synchronize the events.

After you purchase a new subscription you can click the "Check Subscription" button on the "Configuration" panel. If the validation succeeds, you will need to click the "Refresh List" button on the Synchronization panel to make the "synchronize" buttons active again.

How to subscribe to the Sync application

Start your subscription on Sync