Every computer on the HMS network must run an operating system that its maker is still patching. Beginning the week of April 7, 2026, HMS IT is emailing people whose HMS Macs are running a version of macOS that Apple no longer supports with security updates. Each affected person will receive a message from RiskManagement@hms.harvard.edu explaining what their computer needs and the date by which it must be done.
Follow the instructions in your email by the date it gives. After that date, access to HMS services from the affected computer will stop working.
What "a supported operating system" actually means
When HMS IT asks you to run "a supported operating system," it's reasonable to assume that HMS is the one providing support for the operating system, but that isn't the case. While HMS IT provides support for you to access HMS services on your computer, a supported operating system is one for which its company (Apple for macOS, Microsoft for Windows) is still releasing patches as new security vulnerabilities are discovered.
When a vendor stops patching an older version, any flaw discovered after that point stays unfixed on machines still running it. The decision to stop support belongs to the vendor, not to HMS.
The Harvard University Provost's security requirements direct every School to keep its network free of operating systems that the vendor no longer patches. HMS follows that direction through the HMS Vulnerability Management Policy, which allows only vendor-supported operating systems on the HMS network. The goal isn't to push the newest release for its own sake; it's to ensure every computer on the network continues to receive the security patches it needs.
What the emails say
The email you receive depends on the state of your Mac:
- If your Mac is eligible for an upgrade, the email asks you to run it before the deadline. After that date, HMS systems management software will attempt the upgrade for you. If the upgrade still doesn't succeed, signing in to HMS services from that computer will stop working.
- If your Mac doesn't have enough free storage to upgrade, the email asks you to clear space first, then run the upgrade before the same deadline.
- If your Mac is too old to run any currently supported version of macOS, the email explains that the computer needs to be replaced, gives the date access will be cut off, and points to the hardware standards and replacement schedule to help plan a replacement.
If you can't meet the deadline
If the computer is essential for active Harvard research and can't be upgraded or replaced in time, you can file an IT security exception request. For computers that must be replaced, an approved exception might extend access while a replacement is ordered and delivered.