One software license is required per server installation.
An installation is a copy of Signotaur installed on a physical or virtual machine.

Your initial purchase includes a 12 month support and update (minor and major versions) subscription. The license is Perpetual (non expiring). After 12 months you can continue to use the latest version of Signotaur that was available when your subscription expired, or you can renew your subscription for another 12 months and continue getting updates and support.