Editing MacOS version history (section)

{{Short description|History of Apple's current Mac operating system}}
{{For|the history of the classic Macintosh operating system (1984–2001)|Classic Mac OS}}
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The '''history of [[macOS]]''', [[Apple Inc.|Apple]]'s current [[Mac (computer)|Mac]] [[operating system]] formerly named '''Mac OS X''' until 2011 and then '''OS X''' until 2016, began with the company's project to replace its [[Classic Mac OS|"classic" Mac OS]]. That system, up to and including its final release [[Mac OS 9]], was a direct descendant of the operating system Apple had used in its [[Mac (computer)|Mac]] computers since their introduction in 1984. However, the current macOS is a [[Unix|UNIX]] operating system built on technology that had been developed at [[NeXT]] from the 1980s until Apple purchased the company in early 1997.<ref>{{Cite web |last=sandaruwani |first=dilusha |date=2020-08-06 |title=Evolution of Mac OS |url=https://dilushasandaruwani07.medium.com/evolution-of-mac-os-d1afd29eafe5 |access-date=2023-07-05 |website=Medium |language=en |archive-date=2023-07-05 |archive-url=https://web.archive.org/web/20230705095420/https://dilushasandaruwani07.medium.com/evolution-of-mac-os-d1afd29eafe5 |url-status=live }}</ref>

macOS components derived from [[Berkeley Software Distribution|BSD]] include multiuser access, TCP/IP networking, and memory protection.<ref>{{Cite web |url= https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/KernelProgramming/BSD/BSD.html | title=BSD Overview| archive-url=https://web.archive.org/web/20181107021823/https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/KernelProgramming/BSD/BSD.html| archive-date=2018-11-07}}</ref>

Although it was originally marketed as simply "version 10" of Mac OS (indicated by the [[Roman numeral]] "X"), it has a completely different [[codebase]] from Mac OS 9, as well as substantial changes to its user interface. The transition was a technologically and strategically significant one. To ease the transition for users and developers, versions 10.0 through 10.4 were able to run Mac OS 9 and its applications in the [[Classic Environment]], a [[compatibility layer]].

macOS was first released in 1999 as [[Mac OS X Server 1.0]]. It was built using the technologies Apple acquired from NeXT, but did not include the signature [[Aqua (user interface)|Aqua]] user interface (UI). The desktop version aimed at regular users—[[Mac OS X 10.0]]—shipped in March 2001. Since then, several more distinct desktop and server editions of macOS have been released. Starting with [[OS X Lion|Mac OS X 10.7 Lion]], [[macOS Server]] is no longer offered as a standalone operating system; instead, server management tools are available for purchase as an add-on. The macOS Server app was discontinued on April 21, 2022, and will stop working on [[macOS Ventura|macOS 13 Ventura]] or later. Starting with the [[Apple–Intel architecture|Intel]] build of [[Mac OS X 10.5 Leopard]], most releases have been certified as Unix systems conforming to the [[Single UNIX Specification]].<ref name="Leopard UNIX certification">{{cite web|author=The Open Group|title=Mac OS X version 10.5 Leopard on Intel-based Macintosh computers certification|url=http://www.opengroup.org/openbrand/register/brand3555.htm|access-date=2007-06-12|url-status=live|archive-url=https://web.archive.org/web/20080511222112/http://www.opengroup.org/openbrand/register/brand3555.htm|archive-date=2008-05-11}}</ref><ref>{{cite web|author=The Open Group|title=Mac OS X version 10.6 Leopard on Intel-based Macintosh computers certification|url=http://www.opengroup.org/openbrand/register/brand3581.htm|access-date=2013-07-11|url-status=live|archive-url=https://web.archive.org/web/20141116122629/http://www.opengroup.org/openbrand/register/brand3581.htm|archive-date=2014-11-16}}</ref><ref>{{cite web|author=The Open Group|title=Mac OS X version 10.8 Mountain Lion on Intel-based Macintosh computers certification|url=https://www.opengroup.org/openbrand/register/brand3591.htm|url-status=live|archive-url=https://web.archive.org/web/20141116121907/https://www.opengroup.org/openbrand/register/brand3591.htm|archive-date=2014-11-16}}</ref><ref>{{cite web|author=The Open Group|title=Mac OS X version 10.9 Mavericks on Intel-based Macintosh computers certification|url=http://www.opengroup.org/openbrand/register/brand3602.htm|access-date=2013-09-18|url-status=live|archive-url=https://web.archive.org/web/20131104072633/http://www.opengroup.org/openbrand/register/brand3602.htm|archive-date=2013-11-04}}</ref><ref>{{cite web|author=The Open Group|title=OS X version 10.10 Yosemite on Intel-based Macintosh computers certification|url=http://www.opengroup.org/openbrand/register/brand3607.htm|access-date=2014-11-13|url-status=live|archive-url=https://web.archive.org/web/20141110131010/http://www.opengroup.org/openbrand/register/brand3607.htm|archive-date=2014-11-10}}</ref>

Lion was referred to by Apple as "Mac OS X Lion" and sometimes as "OS X Lion"; Mountain Lion was officially referred to as just "OS X Mountain Lion", with the "Mac" being completely dropped. The operating system was further renamed to "macOS" starting with macOS Sierra.

macOS retained the major version number 10 throughout its development history until the release of [[MacOS Big Sur|macOS 11 Big Sur]] in 2020.

Mac OS X 10.0 and 10.1 were given names of [[big cats]] as internal code names ("Cheetah" and "Puma").  Starting with Mac OS X 10.2 Jaguar, big-cat names were used as marketing names; starting with OS X 10.9 Mavericks, names of locations in [[California]] were used as marketing names instead.

The current major version, [[MacOS Sequoia]], was announced on June 10, 2024, at [[WWDC 2024]] and released on September 16 of that year.