As we expected, Apple today released iOS 4.2.1 and brought all supported devices up to the same version of the operating system. You can upgrade by plugging in your device and checking for updates in iTunes.
The update is free for all devices that can run iOS 4, which at this point is every iOS portable device other than the first generation iPhone and iPod Touch.
For iPad owners, iOS 4.2.1 is a very significant upgrade; many of the features that other iDevice owners have been enjoying since iOS 4 was released this past summer are now available on Apple’s tablet. Game Center, folders, tv show rentals, the unified email inbox, and of course multitasking are all now available on the iPad.
All supported devices also receive AirPlay, Apple’s video and audio streaming system that allows an iPhone, iPod Touch, iPad or indeed iTunes itself on the Mac or PC to wirelessly send a playing movie, tv show or song to the AppleTV 2. In addition, AirPlay can also be used to send audio to an AirPort Express or AirPlay-compatible speakers. The first generation AppleTV does not support AirPlay video but should continue to support audio streaming as it has in the past. (Note: AirPlay streaming to the AppleTV requires the device to be updated to iOS 4.2, which is also available today ).
AirPrint is also now enabled on most iOS 4 portable devices (except the 2nd generation iPod Touch), however as many of you are now aware, it does not currently support printing to shared printers connected to a Mac or PC, however there are 3rd party solutions available to turn it back on for Macs. Printing to officially supported printers is of course, working fine, though the list of printers that will work “out of the box” with AirPrint is quite short, being mostly newer HP printers.