Apple has updated its iOS platform to version 6.1.2 specifically to address a serious bug in the way it handles Exchange calendars. The problem, which first appeared in version 6.1, caused excessive logging and usage of resources on Microsoft Exchange 2010-based servers, and also ran down the battery and overtaxed affected iOS devices. Apple identified a fix on Valentine's Day but released it mid-day on Tuesday. The problem also affected Office 365's Online Exchange.