Rainlendar — License R2lic

Deactivate one old computer:

Rainlendar is a popular, lightweight calendar application for Windows, macOS, and Linux. It sits quietly on your desktop, offering highly customizable skins and powerful scheduling features. While the application offers a free Lite version, upgrading to the Pro version unlocks essential capabilities like network calendar syncing (Google Calendar, Outlook, CalDAV) and support for tasks. rainlendar license r2lic

However, based on known information about (a popular desktop calendar application): Deactivate one old computer: Rainlendar is a popular,

Rainlendar licenses are usually per-user, meaning you can use your file on multiple computers that you personally own. To move to a new machine: lightweight calendar application for Windows