XLRotor licenses are perpetual and do not expire. However, periods for Support and Upgrades do expire.
Software upgrades are provided free for all licenses within their active period for Support and Upgrades. One year is included with all new purchases, and is annually renewable thereafter for 15% of the license cost. However, if Support and Upgrades has expired, renewal may be as high as 25% based on months since expiration.
When the XLRotor startup box is displayed by Excel, the date when Support and Upgrades expires is displayed in the startup box. Or, in Excel on the XLRotor ribbon tab, click the button for Program Info on the far right of the ribbon.