Apple today released Sierra, 2016's edition of the Mac's operating system.
Sierra is the first under the "macOS" label Apple introduced in June when it retired the older "OS X" and synchronized the Mac's moniker with other operating systems from the Cupertino, Calif. company, like the iPhone's iOS and the Apple TV's tvOS.
Also known as macOS 10.12, Sierra's launch followed the first "golden master," or GM build, by two weeks.
Sierra was available Tuesday for free download from the Mac App Store. Although the upgrade was not immediately visible on the front page of the e-mart, a search using sierra quickly located the 4.8GB installation file.
According to Sierra'a system requirements, the edition runs on most but not all Macs now running El Capitan: MacBooks and iMacs from late 2009 on; MacBook Pros, Mac Minis and Mac Pros from mid-2010; and MacBook Airs from late 2010 forward.
Also on Tuesday, Apple separately shipped Safari 10 as an upgrade for those running 2014's Yosemite or 2015's El Capitan. (Safari 10 is included with macOS Sierra.) The browser upgrade can be downloaded from the Updates pane of the Mac App Store within Yosemite or El Capitan.
Earlier this month, Apple signaled that it had retired 2013's Mavericks. On Sept. 1, Apple issued an emergency security update for Yosemite and El Capitan, but didn't bother patching Mavericks.
Apple provides security updates to the current version of its Mac operating system -- call it "n" -- and the two most recent predecessors, "n-1" and "n-2." Before today, that labeling system pegged El Capitan as "n," Yosemite as "n-1" and Mavericks as "n-2."
When a new edition appears, as Sierra did today, Apple stops supporting n-2 and moves each version up one notch.