Today, September 15, 2025, Apple released its newest version of the Macintosh operating system, macOS 26 Tahoe. This release includes a series of upgrades to macOS, including a new interface design (Liquid Glass), Continuity improvements, productivity enhancements, and minor improvements to Apple Intelligence. macOS 26 is also a component of Apple's new operating system numbering schema.
Information Systems & Computing (ISC) strongly recommends that all University users adopt a "wait and see" approach and continue using earlier macOS versions for at least one week following this release. This period allows time for any initial bugs and compatibility issues to be identified and fixed. ISC suggests that administrators of institutionally owned systems block the upgrade and that users of individually owned systems ignore Apple's upgrade prompts. ISC will send an update on Tahoe's status at the University on September 22.
macOS 26 Tahoe is compatible with all Macs released in 2020 or later, along the 2019 versions of the MacBook Pro 16-inch and Mac Pro. It is also the final version of macOS that will work with even the most modern Intel-based Macs. Tahoe is not currently pre-installed on new Macintoshes, but that will change over the next few months. The University's Recommended and Supported Operating System Lifecycles at Penn charts have been updated with preliminary Tahoe guidance.
The release of macOS Tahoe starts the retirement clock on the University's remaining affiliated Intel-based Macs, which are currently slightly under 19% of Penn's macOS installed base. Users of these systems should plan to replace them no later than June 2028.