The source of the battery-draining bug that sucked the life out of iPhones, and strained mobile phone and corporate networks, has been identified by Apple as a cock-up between its iOS calendar app and Microsoft Exchange servers.
The flaw affects people synchronising their Microsoft Exchange calendars with their iOS 6.1 devices. Unlucky fanbois triggered the software flaw by performing a calendar action of doom that caused their iThing to constantly contact the Exchange server.
When an exception was added to a recurring calendar event - for example changing an event for a one-off day - the calendar program repeatedly synced with its Exchange servers. That flooded networks with packet traffic and burned through 3G mobile data allowances, draining the device's battery and sometimes causing the servers to block the gadget.
According to a write-up on the Apple Support Forums, disabling then enabling the connection to the Microsoft Exchange server should clear the problem: ie, turn it off and on again.
Meanwhile, iPhone 4S owners using iOS 6.1 have experienced connectivity problems on 3G networks: Vodafone UK and Three Austria were two mobe operators who admitted their systems were struggling to cope with the phones and pleaded with customers using iPhone 4Ses to not upgrade to iOS 6.1 until the issue was fixed.
Apple has since cooked up a software update, released as version 6.1.1 of the phone operating system, that claims to squash that radio connectivity bug. ®