Once expired, you can still renew your ItemPath license at any time, but until you do, ItemPath will no longer be running.
If ItemPath is installed on-premise, all your settings (i.e. reports, dashboards, workflows, users, etc.) will be saved as-is until ItemPath is reactivated. However, cloud installations will be permanently deleted one month after expiry.
In most cases, a support agreement will expire at the same time as an ItemPath license. This means that you assume responsibility for any issues as a result of the lapse.
Note: There is a 30-day grace period for renewal payments to come in, but a Purchase Order will need to be sent before the expiry date in order for ItemPath to remain functional.