That depends on the software license model you're using.
If you do not know what type of software license you are using now, then consult the software licensing troubleshooting guide to determine this.
Software subscription licenses are monthly or yearly subscriptions for OpenVPN Access Server VPN connections. They are valid for a predetermined period and can be set to renew automatically. Renewing a subscription on our Access Server Portal will take effect immediately on any Access Server that is using that subscription. So any changes you make to the subscription, even changing the size of the subscription, takes effect immediately. If you allow a subscription to end and you do not have it set to renew, then the Access Servers using this expired subscription will eventually only allow 2 concurrent VPN connections. You will receive email notifications before a subscription needs to be renewed.
Fixed license software licenses for OpenVPN Access Server are valid for a predetermined amount of time, and require action on your part to renew. When you purchase a fixed license activation key, the choices are for a period of 1, 2, 3, 4, or 5 years. At the end of that time, when the license key reaches it end date and expires, it will disappear off your server automatically. If the last license key on your Access Server expires, it allows only 2 concurrent VPN connections. When you renew within the last month before the fixed license key is going to expire, then the Access Server has the ability to retrieve the renewal key automatically. You can also force this renewal retrieval immediately by going to the Admin UI and clicking the Get renewal keys button. If the key has already expired you'll have to go in and activate the new key yourself. You will receive email notifications before a fixed license expires.
Amazon AWS tiered instances have no end date for the license. They are licensed as long as the Access Server is up and running on Amazon AWS. The billing for the software license is hourly and can be changed to annual so that you get a discount. For information on that we recommend you read the pricing information carefully on the AWS Marketplace offerings for OpenVPN Access Server with a specific allowed amount of connections. Software license billing for such an Amazon AWS instance only stops when the instance is in 'stopped' state, or 'terminated'. This is billed directly through Amazon AWS.
Perpetual type license keys which were sold in the past will still continue to function on the original hardware and software they were activated on, as per the conditions for the perpetual license keys.