Apple has confirmed it cannot fix a bug that has woken thousands of iPhone owners every night since January 1.  The phone’s ‘do not disturb’ feature is designed to silence the handset during set hours to prevent any disturbance while users sleep or if they are in a meeting.  However, it stopped working on New Year’s Day, and the firm today confirmed it will not work again until January 7 to a glitch in the way Apple’s software deals with dates.  ‘After January 1st, 2013, Do Not Disturb mode stays on past its scheduled end time,’ Apple said in a statement on its support site.  ‘Do Not Disturb scheduling feature will resume normal functionality after January 7, 2013.