About macOS Versions
Apple releases a new major version of macOS per year, usually end of summer / early fall. Apple makes no committment for the date until which any given OS version is supported. In general the three most recent releases receive security updates, but we have seen cases where a new major version was released without the corresponding security updates for previous versions.
It is the users reposibility to ensure to always run a supported version of macOS.
We assume that at the time being the following versions of macOS are supported:
If you use a Mac that runs a macOS version older than 11 you should check whether the device can run at least 11 and upgrade as soon as possible. If that device can not run 11 you should consider replacing it as soon as possible.
To ease the upgrade for the stragglers we have kept some of the documentation of the more recent unsupported versions:
Upgrades to the latest macOS version can easily be done via the "Software Update" pane in "System Preferences". Instructions how to upgrade to other versions of macOS can be found on Apple's HT211683.