A software license model in which the customer is granted lifetime rights to use the technology in exchange for a one-time upfront fee. Perpetual licenses were the predominant model use by software companies between 1990 and 2010, but in recent years have been replaced by subscriptions and as-a-service models. Pricing for perpetual licenses is typically based on the number of named or concurrent users, the number of CPUs it runs on, or the customer’s annual revenues. To receive upgrades and bug fixes, customers with perpetual licenses must purchase an additional software maintenance agreement on an annual basis.