I am posing this question because I don't see an answer anywhere online, other than for "features". OS for the past 3 versions will get security fixes. So what's the point? I ask because I have a boss who is posing this question. He sees no reason to update a Mac once in place to any new OS until it's replaced 3 years later. Most everyone in IT cringes at this from a feature and security standpoint but we can't seem to drive the point home. I am trying to find an article(s) - respectable - that I can link him to - that explain the importance of updating you're OS. Not having 3/4 different MacOS versions floating around that are harder to maintain from a system admin side of things (multiple different patch versions and variants). Etc. Anyone have any advice or links that would help make my case?