Everyone can thank my day job for keeping me so busy throughout 2017 that I could never spare the mental bandwidth to get our web server upgraded. It is not the upgrade, itself, but the expected rapid error-fixing after.
The big work project is (almost) done, and I will get my brain back to work on these sites, again. I have informed our web hosting company that the upgrade will be done in late March.
So sometime around the Spring Equinox: March 21-22.
As previously mentioned, the server upgrade will kill FlashChat.