Over the last three years, since the release of iOS 7.0 on 18 September and OS X 10.9 on 22 October 2013, Apple’s release schedule has been growing steadily more regular, and might even – disasters excepted – be fairly predictable.
That pattern of major version releases repeated in 2014, with iOS 8.0 on 17 September and OS X 10.10 on 16 October, and last year, with iOS 9.0 on 16 September and OS X 10.11 on 30 September.
Unlike the major releases, which occur on separate days with at least a week between them, subsequent minor releases are normally synchronised to the same day; the exceptions to this are security patches for iOS and urgent fixes. The burden on Apple’s servers and support lines, and that on users, to attempt major releases on the same day is just too great to contemplate.
The disadvantage with separating major releases of macOS and iOS is that co-ordinated features which require both Mac and devices to be upgraded will have limited functionality (or not work at all) to begin with, until macOS has caught up with iOS. It is possible that Apple has built in some upward compatibility in the recent Security Update 2016-001 for El Capitan, which might explain its size.
So if you do have both Mac and iOS devices, expect some of the integrative features of iOS with macOS to be limited to begin with, on 13 September. Hopefully those will be rectified when macOS Sierra is released the following week. This could affect Universal Clipboard, Auto Unlock using an Apple Watch, and some features of iCloud Drive.
This year, Apple has already announced that iOS 10.0 will ship on 13 September, and macOS 10.12 on 20 September. It is not hard to deduce that we should expect iOS 10.1 and macOS 10.12.1 to be released around 12 or 19 October, and iOS 10.2 with macOS 10.12.2 around 30 November 2016. With each of those will come tvOS and watchOS updates as appropriate.
Apple prefers to release updates around the middle of the week, although in the past it has opted for Mondays instead. The most likely days for release of future updates are therefore Tuesday to Thursday.
So if you’re a later updater who prefers to let the first minor update or two roll out before upgrading, you should look to do that in mid or late October (10.12.1+10.1), or early December (10.12.2+10.2), by which time the dust should be settling. Sticking with El Capitan (10.11) and iOS 9 a little longer should not compromise your security, as Apple will release simultaneous security updates for them, and should continue to do so for Yosemite (10.10) too.
If you’re intent on staying at the bleeding edge, and must get upgraded/updated on the day of release each time, you should mark those dates in your calendar and keep close to a fast internet connection on them. Of course those dates may change substantially in practice, although with multiple development teams all working to co-ordinated release dates, Apple has much less flexibility now that it had in the past.
Think what it will be like when there’s your Mac(s), iPhone(s), iPad(s), Watches, AppleTV(s), and an Apple Car or two…