During registration, you will only be able to add current certifications to your Professional Briefcase. If a certification expires after registration, you will still be able to work per diem jobs that don't require that specific certification. If your license expires after registration, you will not receive any job notifications until you renew your license.
You will receive emails reminding you to renew your license or certification. Mobile alerts are sent periodically, starting 3 months prior to the expiration date, to give you plenty of time to renew your license or certification. You need to have an active license at all times to receive job notifications.