Hello,
Thank you for contacting us. Zoiper Classic Biz license is to be purchased one time only.
Zoiper Classic Biz is licensed per OS / per seat. Each license is to be activated on one device only. In case there is more than one operating system on your device, you will need to purchase a BIZ license for each of them.
If you need to move your license to another device you would need to reset your certificate.
Each certificate can be reset up to 3 times, then, if you need to move your Zoiper again, you will need to purchase a new license.