An update can only be used to update your existing installation otherwise the key will be wrong and AIM won’t start.
If you are re-platforming your production server, I would do a new install on the new server - which will give you a 30 day eval, get everything working on the new server, then contact Vlad for a new key. Keep in mind that as soon as the new key is generated for you, the old server will stop working.
I must say it’s really about time that AIM had a method of being able to register and de-register servers online (a la Office 365 and a host of other apps) having to call Vlad is a bit archaic to say the least.