Hi @zerogravity994,
spacedesk is free for private non-commercial use. Only free version does expire. Paid business license does not expire.
Currently availability of business license is limited to Google Play Store for Android. Soon, iOS and Windows business version will follow in Apple Store and Microsoft Store. In the meantime iOS and Windows Viewers can be used for free even by business users.
Upon expiry, screen will turn to black and white (no more colors). This only happens in the non-commercial version of the Viewer.
Upon expiry a new version of the spacedesk Driver needs to be downloaded from the spacedesk website.