Look for the most recent macOS update and check which versions of macOS it was released for. It contains a list of security updates Apple has recently released for all its devices, including Macs running macOS. The Apple Security Updates page is the only page on Apple’s website that gives you this information. But Apple provides no guarantees, and that’s just an informed guess. So, assuming Apple releases a new version of macOS every year, each release of macOS will be supported with security updates for roughly three years. For quite a few years, Apple has consistently updated the last three versions of macOS-in other words, the current release of macOS and the last two releases-with security updates. For example, you can see on that page that for Windows 7 Service Pack 1, mainstream support (new feature releases and minor updates) ended in 2015, but extended support (security updates) goes on until 2020.Īpple does still has a plan, though, even if they don’t describe it publicly. Microsoft publishes their Windows support lifecycle, which spells out precisely (and guarantees) how long each product will receive different types of updates. This is very unusual if you’re used to dealing with Microsoft Windows.
They just stop releasing updates for old versions of macOS with no announcement, and you’re on your own. Apple doesn’t even publicly say when an operating system is “end of life” and is no longer receiving updates. Apple doesn’t provide a written statement that guarantees how long it will support each release of macOS with security updates.