If you move to a new server or domain, it’s fine to take your current license along with you. But you my need to renew your service plan if it has expired.
I’m moving my Big Medium installation to a new server or domain. Do I have to buy another license?
No, you can continue to use your current license. No need to purchase another.
A Big Medium software license allows you to run a single installation of Big Medium, and the license is not limited to any particular server. If you move to a new server or a new domain URL, it’s fine to take your current license along with you. (You need to purchase new licenses only when you add additional live installations of Big Medium: e.g., two licenses for two concurrent installations.)
You may, however, need to renew your service plan if it has expired. A current service plan is necessary to activate new installations of Big Medium, including re-installation at a new server or when you change the domain where you host Big Medium. Find out more about the Big Medium service plan.