What would be the preferred steps I'd take to upgrade this particular system?
The system is at the moment hosting a production server using VirtualBox (so keeping downtime to a minimum is important.) Ubuntu itself is not hosting anything else -- just VirtualBox.
I am thinking of cloning the production server (not the system that needs upgrading) to a different box that could temporarily host the server during the upgrade process. And later to clone it back to the upgraded system.
I do intend on using the upgraded system the same way as before, not hosting anything but just using VirtualBox.
For the upgrade:
Would a clean install be preferred? I tend to think so -- but would love to be proven wrong. (Having to reconfigure the network configuration is the thing I am worried about and not looking forward to.)
And -- should I skip 18.04 and go straight to 19.04? (Not sure on this; and again, would this need to be a clean install? Or should I got 17.10 to 18.04 to 19.04?)
And should Desktop or Server be installed for a clean install? What would be quicker?