Apple's OS X El Capitan appears to be on track for a late September release, according to a comparison of its preview release tempo with that of 2014's Yosemite.
The eighth preview of El Capitan, also known as OS X 10.11, was issued to registered developers today.
Although Apple does not commit to OS X release dates until just days before the debut, if then, the eight builds of El Capitan's developer preview caught up to, then edged past, the timing of the same-numbered builds for last year's Yosemite.
As of today, El Capitan is 15 days ahead of Yosemite's cadence.
In 2014, Yosemite first reached developers on June 2, then ran through seven more builds, the last released on Sept. 15. Two weeks later, on Sept. 30, Apple issued the first of several "gold masters," or final code candidates, which led to an Oct. 16 delivery to the Mac App Store.
El Capitan, unveiled June 15 at Apple's annual developers conference, was out the gate nearly two weeks behind Yosemite but caught up with the fourth build, released July 21. Since then, El Capitan's developer previews have been one or two weeks earlier on the calendar.
The faster pace hints at an El Capitan launch sooner rather than later. If Apple hews to the same general timeline as last year -- and considers the eighth preview its final before gold master, as it did in 2014 -- the upgrade has a strong shot at shipping by September's end.
That would be two weeks earlier on the calendar than Yosemite, but about a month after OS X Snow Leopard, aka 10.6, which shipped on Aug. 28, 2009. Snow Leopard is an important comparison because it followed the much more significant upgrade OS X Leopard of 2007, and was billed as a polish on its predecessor. Apple has touted El Capitan in much the same way, as a performance, stability and reliability improvement over Yosemite.
In previous schedule comparisons, Computerworld bet on a late-August to mid-September launch of El Capitan because of the similarities between that edition and Snow Leopard, as well as an accelerating pace of El Capitan. Its tempo, however, has not quickened since its sixth preview.
Apple will host an event Sept. 9 in San Francisco, where it's expected to unveil the latest iPhones and a redesigned Apple TV, as well as set a release date for iOS 9. It could also take a few minutes out of what will certainly be a long presentation to peg the launch date for El Capitan.