I'm reaching here, but it looks like the push of MacOS updates is a bit different than that for iOS, in that once an update is available, even if not yet 'pushed' a simple selection on iPhone or iPad through settings / software update will find, then download, and install the update. Not so at least with my iMac. I can't remember if I've ever been able to 'go looking' successfully for an update to MacOS which is in theory available but hasn't dropped. Using the 'update' icon only gets a spinning wheel for a few seconds then a message to the effect of 'No Update Available.'. It's not a crunch situation in the least, but High Sierra introduced a few buggy issues ( which I have found workarounds for) so in my mind, I'd update away from it only as soon as practicable. It's performing very well as long as it NEVER goes to sleep / hard-drive spin down, so other than once when I was away a few days, and a few re-boots from power outages, the HD has been active and spinning since last January..... If a computer is used as a server that 24/7 use is normal without issues so I don't really worry a lot. I use a screen saver then 'screen only' sleep. I installed internal temperature display software which works fine and even though the iMac is on the desk in a non air conditioned room all temps are always well away from any critical zones. I also do a monthly backup to an external drive through Time Machine. I live in the Caribbean where temps are usually 30+ in the day and 25+ at night.
Part of me says ' if it ain't broke.......', another says "do the update which may solve the issue ( the sleep situation)" BUT as of yet the update hasn't dropped here in the Caribbean, and trying to manually grab it doesn't work either....
Part of me says ' if it ain't broke.......', another says "do the update which may solve the issue ( the sleep situation)" BUT as of yet the update hasn't dropped here in the Caribbean, and trying to manually grab it doesn't work either....