This thread will contain updates about the server move and OS upgrades I started today. So far, we've bumped up a minor version number in the operating system with apparent success, and now an update to about 400 installed software packages is in progress. To this point, only quick reboots have been necessary.
The next step is a more major OS upgrade, which I plan to attempt this evening. If that hits any major snags, we'll be offline until I can get to the physical machine on Tuesday morning. Ideally, it should again just be a few quick reboots.