Apple says the end of daylight savings time could cause problems for iPhone users. On their website, they stated that repeating alarms set on iPhones and some versions of the iPod touch may not recognize the end of daylight saving time and may work incorrectly shortly before or shortly after the Sunday morning time change. Devices using the mobile operating system iOS 4.1 are most likely to experience these problems. Apple recommends turning off repeating alarms and setting them manually until Monday, when it’s safe to set them to repeat again.
