The OLD Xserves we were using were starting to be difficult to upgrade. We tried to upgrade the OS, no go. Tried to upgrade services, no go. Mostly because the hardware was no longer supported, which caused the upgrades to state that hardware wasn’t supported. Even minor upgrades were becoming major headaches. SO we upgraded, from 10.6 to 10.12 Sierra. LOL. Not the end all but so far it has paid off. Also the hardware had to be upgraded, xserves, ALL of them, gotta go. Now we are using MacMinis, must admit is is quieter.
The effects kinda snow balled. Hard drives format weren’t readable, services needed to be upgraded, some things don’t work. Trying to find workarounds is the biggest pain. Jabber/Messages is a big one, however now there is something called MQTT. We are trying.
On a positive note our Raspberry Pico W’s have started to arrive. Weather station conversion finished and posting data. We are working on another one that’ll be mobile.