I'd like to exchange these bugs —

Apple fixes Exchange (but not passcode unlock) bug with iOS 6.1.2

The update fixes only one of the two high-profile bugs from iOS 6.1.

iOS 6.1.2 brings a microscopic but important list of changes.
Enlarge / iOS 6.1.2 brings a microscopic but important list of changes.
Andrew Cunningham

Apple has released the promised iOS 6.1.2 update today to fix the Exchange bugs that have been plaguing users since the release of iOS 6.1. The bug caused iOS devices connected to Exchange servers to over-poll calendars and mailboxes, leading Microsoft to recommend that administrators block or throttle iOS devices until the bug was fixed.

The release notes only mention the Exchange issues, but we wanted to check to see if the passcode unlock bug from iOS 6.1 had also been fixed. We tried the convoluted unlock exploit on our own iPhone 4S and were able to unlock the screen successfully under iOS 6.1.1, and the same process once again unlocked the phone in iOS 6.1.2, giving us access to the phone dialer app and all of the information contained within. Put simply: it doesn't look like this update fixes the passcode unlock bug, according to our testing.

If you're worried about your device's security, turn off the "simple passcode" feature on your phone and use a more complex, alphanumeric passcode instead—reportedly, complex passcodes are not subject to the same security flaw. Update: commenter Kosh_179 says that using a complex password also won't protect you from the exploit. In that case, we'll have to wait for Apple to fix the problem.

Users who need the update can grab it over the air or via iTunes. While iOS 6.1.1 was available only for the iPhone 4S, iOS 6.1.2 applies to all devices supported by iOS 6: the iPhones 3GS, 4, 4S, and 5; the iPad 2, iPad mini, and both Retina iPads; and the fourth and fifth-generation iPod Touches.

Channel Ars Technica