Apple announced today that it has identified the cause of a sync problem between iOS 6.1 devices and Microsoft's Exchange service and said that it would issue a fix in the next software update.
Almost immediately after Apple release iOS 6.1 at the end of January, Microsoft Exchange administrators noticed that devices running the new OS version were causing "excessive logging" on servers. The issue was traced back to Apple code used to synchronize a user's Exchange mailbox and calendar events.
The announcement, made on Apple's support page, did not indicate a time frame for that software but offered advice for avoiding the issue:
Apple has identified a fix and will make it available in an upcoming software update. In the meantime, you can avoid this bug by not responding to an exception to a recurring event on your iOS device. If you do experience the symptoms described above, disable then reenable the Exchange calendar on your iOS device ...
Apple pointed out that affected users may notice increased network activity or reduced battery life on their iOS devices. The increased activity will appear on Exchange Server logs and may lead to the device being blocked. The issue affects iOS 6.1 devices running Microsoft Exchange 2010 SP1 or later, or Microsoft Exchange Online (Office365).
On January 28, Apple released iOS 6.1, the first major update to iOS 6 since September. Along with a few new minor features and bug fixes, the new software also prompted numerous reports of sudden and significant battery drain and at least one case of an overheating battery. Suspicion immediately fell upon the excessive logging issue with Microsoft Exchange.