Apple releases an upgrade to macOS yearly in the Fall. Learn how LITS plans for and supports these changes.
About macOS upgrades and updates
This terminology is not standard across the IT industry, but it helps to understand the difference in the context of Apple devices.
What is a macOS update?
Apple refers to changes within one named version of the operating system as "updates." Updates mainly provide security patches, though they can at times bring smaller changes to new or existing features.
Example: The minor release to patch macOS 15 Sequoia from 15.6.1 to 15.7 is an example of an update.
What is a macOS upgrade?
Moving from one named version to another is an "upgrade." Instructions on how to upgrade to a new macOS named version when available.
Example: Running Software Updates to go from macOS 14.7.8 Sonoma to macOS 15.6.1 Sequoia is an upgrade.
Upgrades may introduce compatibility issues with 3rd party applications. LITS enforces an upgrade deferral period of up to 90 days from the release date to allow for testing.
How does MHC manage macOS updates and upgrades?
Our Mac management system allows us to control when updates and upgrades are "seen" by computers. Because major upgrades require planning and testing, we defer major releases by up to the maximum allowed 90 days from the time Apple releases it.
Which versions are supported?
Apple officially supports only the current OS version. As of September 15, 2025, this is macOS 26 Tahoe. Still receiving updates are macOS 14 Sonoma and macOS 15 Sequoia.
Apple officially supports only the current OS version. As of 15 September 2025, this will be macOS 26 Tahoe. Important vendors such as Microsoft only support the current version plus the previous two versions (commonly referred to as N, N-1, and N-2).
This means that every fall, the 3rd oldest version of macOS falls out of support for software such as MS Word and Excel. Because we rely on patches to Microsoft applications, as a campus we can't support operating systems older than N-2.
Historically, Apple has been releasing the last security update for a given operating system in July of the third year since it was released (the N-2 release), so that gives each OS an active lifespan of about 2 years and 10 months.
In 2025, with the release of macOS 26 Tahoe, Apple is using the 2-digit year of release, in new-car-model-year style, as the OS version number, instead of simple incremented number.
Supported macOS versions and last release dates
These are the macOS operating systems of the last 10 years, along with the date that the last patch (update) was released for that version.
- macOS 26 Tahoe - initial release date 15 SEP 2025
- macOS 15 Sequoia - currently patching/getting updates
- macOS 14 Sonoma - currently patching/getting updates
Unsupported macOS versions and last release dates
- macOS 13 Ventura - 20 AUG 2025
- macOS 12 Monterey - 29 JUL 2024
- macOS 11 Big Sur - 11 SEP 2023
- macOS 10.15 Catalina - 20 JUL 2022
- macOS 10.14 Mojave - 21 JUL 2021
- macOS 10.13 High Sierra - 12 NOV 2020
- macOS 10.12 Sierra - 22 JUL 2019
- OS X 10.11 El Capitan - 9 JUL 2018*
- OS X 10.10 Yosemite - 19 JUL 2017*
- OS X 10.9 Mavericks - 18 Jul 2016*
* OS X references a Roman numeral 10 and is pronounced "oh-es-ex."
macOS upgrade testing and lifecycle
LITS's goal is to make the transition to new versions of macOS as easy as possible. We test new operating systems to make sure they are compatible with our management tools and essential applications.
Test Stage (Summer/early Fall)
Apple announces the upcoming major release of macOS every June at the World Wide Developers' Conference. CTS staff participate in beta testing and identify potential challenges or changes that will need process changes or documentation.
New OS announced/beta testing
- CTS staff participate in beta testing program AppleSeed for IT
- Test new beta releases against deployment and maintenance processes
- Provide feedback to Apple
- Annotate processes for changes
Release preparation/Beta period
- Prepare a Software Restriction in Jamf (Mac management system) to block the coming OS installer app from running
- Check all configuration profiles that include a Restrictions payload to ensure that profiles set a 90 day delay for upgrades on production systems
- Draft documents on changes
- Reiterate process changes
Expiring OS expecting last updates in July
- Begin messaging about updates to the currently supported version
- Provide Self Service action item to facilitate updates to currently supported version before the new fall release confuses the issue
Release Day (early-mid Fall)
On release day we may hear questions about the availability of the upgrade. We let people know that the new version will be available generally after 90 days. Folks can join Early Adopters for earlier access (once internal testing is complete and the campus is not in a busy point of the semester).
New OS on release day
- Enable Software Restriction with the confirmed release name
- Finalize user documentation about the upgrade release
- Plan for Early Adopters testing (Early Adopters opt-in)
Expired OS on release day
- Continue messaging about upgrades to a supported OS version (preferably the new N-1)
Early Roll-out (mid-semester through late Nov)
Once we're ready to support the first users, we can allow Early Adopters to upgrade. They can let us know about any changes they find significant, as well as any compatibility issues with less common software and hardware.
- Early Adopters testing (after internal LITS testing is complete)
- Update user-facing information
- Disable Software Restriction for Early Adopters
- Track adoption percentage
- Reminder about upgrading from the older, newly retired OS
Main Adoption Stage (J-term/spring break)
Once the 90 day deferral period is up, we can promote and encourage folks to upgrade when ready. We encourage readiness with documentation, news updates, drop-in support.
- Recommended Upgrade Period
- Advertise desirability of upgrade to faculty and staff
- Communicate helper information (backups, new feature information)
- Announce recommended deadline
- Reminders of Helpdesk appointment availability for upgrade assistance
- Self Service upgrade action
- Reminders about the retirement of the older OS
Wind-down (mid spring/early summer)
We'd love to see everyone on the new operating system by mid-spring!
- Communicate upgrade deadline; provide helper information
- Request for assistance with upgrade via Helpdesk
- Self Service upgrade action
- Planning academic labs based on the new OS
- Track adoption percentage
The cycle begins again . . .
In June, Apple announces the next version of macOS at the World Wide Developers' Conference.