macOS Big Sur (version 11) is the 17th and current major release of macOS, Apple Inc.'s operating system for Macintosh computers, and is the successor to macOS Catalina (version 10.15). It was announced at Apple's Worldwide Developers Conference (WWDC) on June 22, 2020, and was released to the public on November 12, 2020.
macOS Big Sur features a user interface redesign and a revamp of the Time Machine backup mechanism. It is also the first macOS version to support Macs with ARM-based processors. To mark the transition, the operating system's major version number was incremented, for the first time since 2000, from 10 to 11. The operating system is named after the coastal region of Big Sur in the Central Coast of California.
Providing some indication as to how the pre-release operating system may have been viewed internally at Apple during its development cycle, documentation accompanying the initial beta release of macOS Big Sur referred to its version as "10.16", and when upgrading from prior versions of macOS using the Software Update mechanism to early beta releases, the version referred to was "10.16". An exception to this was the Developer Transition Kit, which always reported the system version as "11.0". macOS Big Sur started reporting the system version as "11.0" on all Macs as of the third beta release.
To maintain backwards compatibility, macOS Big Sur identifies itself as 10.16 to software and in the browser user agent.
