MacStories is claiming a "reliable source" has told them Apple was previously targeting a December release for their next update, iOS 4.3 for iPhone, iPod touch, and iPad:
when Apple didn’t know about the WiFi issues in the GM seed of iOS 4.2, the OS was scheduled to be released weeks before Nov. 22nd. Apple found out about the WiFi issues, released a second GM build and iOS 4.2 came out yesterday. It came out in November, but it should have been out in the first half of November. Anyway, before the WiFi issues were discovered, Apple was already planning to release a new build of iOS 4.x in mid-December. Most specifically, they were planning for an iOS 4.3 release on December 13th, which is a Monday.
Our source tells us it is unclear whether the “extra time” that was required to ship iOS 4.2 (actually, it’s iOS 4.2.1) will cause a delay for the rumored release of iOS 4.3 on December 13th or not. iOS 4.3 should, however, include bug fixes and maintenance of the code. It’s likely that 4.3 will also address the initial issues found in AirPlay, but we can’t confirm this just yet.
This is all supposed to tie in to the rumored App Store subscriptions Apple may be about to launch alongside Newscorps' The Daily iPad newspaper app, and the also rumored December Apple special event with Steve Jobs and Rupert Murdoch.
Unlike hardware refreshes where Apple has stuck to reliable yearly schedule so far, software updates have been all over the place. iOS 4 came out in June. iOS 4.1 came out in September. iOS 4.2 came out just yesterday (November). iOS 3 only ever went to iOS 3.1.3 in February 2010. iOS 2 went to version 2.2.1 in January 2009. iOS 1 went to 1.1.4 in February 2008 (not including an iPod touch-only 1.1.5 security fix).
Could we really see iOS 4.3 in December, a month or less after the last update? Give us your guesses in the comments!