Guidelines for upgrading freeradius installation? (3.0.19 -> 3.2.8)

[uj2.hahn at posteo.de]

Hi, all!
Years ago (2020) I implemented a pretty basic freeradius installation 
(authentication only) in a school for WLAN access.
That time I installed version 3.0.19 on a virtual server (Ubuntu 19.04) 
and used Samba to
connect to Active Directory on Windows Server.
This is still working fine but I think it is time for a larger upgrade 
of all involved components.
Is there any recommendation/cookbook/guideline how to do that upgrade in 
the most efficient way with
minimal effort?
Of course I can do everything from scratch on a second virtual machine. 
Is that the preferred way? Or can
I copy the freeradius configuration over? Any changes I have to do then?

Your help is very welcome!

Regards
Uwe