The license is a one-time fee.
You can download each new releases and apply your license to it.
Once you bought your license, it is yours.
If you make money out of the games you are making with personal license, you'll need to upgrade to business license once you made over 5000$.
All this can be found in the "how C2 license work" or store's licensing. You can find those informations in the "License" tab for each license in the store as well.