Licensing question (development server)

[md_detroit]

Just a few quick licensing questions.

We have a current Zimbra environment running very old 6.0.6GA (RHEL5). It is my plan to launch a separate Zimbra development server in our environment and install the latest version of Zimbra on it to use for testing purposes for when we eventually plan to upgrade our current environment.

My question is, in order to turn on all the features we have with our current environment (3000 users, A & D, etc.), can I just use our current license we have on the production server with the development server (basically two servers running concurrently with the same license - different mail stores of course) or will that:

a) violate the license agreement?
b) disable features / licenses on the production server?
c) both of the above?
d) require another license purchase or issue of a temporary license?
e) nothing detrimental will happen - everything will continue to run?

I would prefer to not test an upgrade by using the production server, since we have over 2000 active users, but to test the latest version using a couple of users from our current installation, on a separate server.

Thanks