Xenforo upgrade pricing

[mcl]

I've recently purchased a website that uses Xenforo. How do I know which version they are running?
They are running it on a server with PHP 5.6 and I'd like to port it over to a PHP7 server so I'd like to upgrade Xenforo. What would the upgrade pricing be? Also, depending upon the version number (their current version is most likely no more than 18 months old), how much breakage can I expect? [The forum is not the most important functionality of their site but they use it for user registration flows.]

Thanks for the help!

 

[Paul B]

You will need to have the license transferred to you in order to post in the customer forums and obtain support.

If it has already been transferred, you will need to associate your forum user name with your license.