I wondered if some one would be able to clarify upgrade/installation of nintex Wf.

We have recently rebuilt our test environment and therefore need to do a new install of Nintex WF 2010.  Do I just run the latest installer, or are there separate upgrade packages?  I'm asking as our Prod environment also needs upgrading but I'm not sure if it's only one installer or are there several?

Sorry if this is a bit mumbled, not quite sure what I need to ask..

Thanks in advance of anyone's help.

Claire