Subscription licenses are month-to-month subscriptions, and include the Support/Maintenance.
Traditional licenses are one-time purchases (perpetual licenses), and come with 30 days of Support.
We do encourage our traditional license-holders to maintain an accompanying, annual Support subscription for access to technical support (email, phone, remote sessions, chat) and access to all software upgrades.
When a traditional license is purchased, the license is connected to the software for that year. When the software is upgraded each year, it is necessary for traditional license-holders to have Support in order to receive the required new license to upgrade.