macOS is no longer officially UNIX

Apple quietly let its UNIX certification expire, dropping macOS from The Open Group's official register.

Apple did not renew its certification with The Open Group, quietly removing macOS from the official register of UNIX systems. Only operating systems fully compliant with the Single UNIX Specification are allowed to use the trademarked UNIX name.

Why it matters: Official UNIX certification serves as a vendor-neutral benchmark for system stability, maintainability, and backward-compatibility. It guarantees consistent service behavior across suppliers so developers can port code without getting locked into one platform. Losing the badge does not break your command line, but it ends Apple's formal commitment to meeting that global standard.

Know this: The Open Group's certification covers platforms from mobile devices to mainframes, aiming to ensure application portability and standard interfaces across different hardware vendors.

Your terminal scripts will still run fine, but macOS is officially off the UNIX guest list.