Background Information
As inconvenient as updates can be due to required restarts and interruptions, software updates remain critical to modern business computing environments. With the prevalence of remote work, and storing, accessing, and processing of data, devices are prime targets for a variety of computing attacks. As a result, software developers, namely Apple and Microsoft, routinely release security patches to address vulnerabilities, and our job is to ensure that our devices are kept up-to-date with the latest patches.
It is recommended to read up on SMPH’s official policy that requires the installation of updates within 45 days.
Upgrades vs Updates
Apple releases both “updates” and “upgrades” for macOS systems.
An update is a newer version of the currently installed macOS, such as an update from macOS 15.0 to macOS 15.1 or 15.2.0 to 15.2.1, which are all referred to as “Sequoia.” On the other hand, an upgrade is a major new version of macOS with new features and a new name, such as the upgrade from macOS Sonoma 14 to macOS Sequoia 15. The naming schema may be Apple’s way of making taking about versions easier.
macOS updates are released roughly once a month, while upgrades once a year. Latest release dates are posted here.
Apple only supports the latest released major version of macOS plus the previous two releases. Currently supported releases can be viewed here.
Where to Install Updates on Your Mac
Legitimate macOS updates and upgrades can be found in the Settings app on your Mac, pictured below: 
A red badge with a number (similar to iPhone notifications) indicates that there is an available update (or upgrade) for your Mac.
Apple has instructions on how to perform updates on your Mac in this article titled Update your Apple software.
Nudge
In order to keep department-owned devices updated and in compliance, a mini-program called “Nudge” is installed on all macOS devices. Nudge will repeatedly remind you that updates are needed and when they should be installed. The option to defer updates exists, however, the option is no longer available when the deadline is reached. This small program is designed to become increasingly assertive as the deadline approaches with the goal of “nudging” the user to install the update.
When Nudge appears, the “Update Device” button launches System Settings to install the update.