However according to a report from AppleInsider, it seems that the update to iOS 9.1 comes with a bug that disables the person’s alarm clocks when it is updated overnight. Many users have taken to Twitter to voice their displeasure at the bug, especially since there are probably many out there who need the alarm clocks to wake up for work, school, or other important meetings.
This isn’t the first time that iOS has been affected by alarm clock bugs. If you’re someone who absolutely needs the alarms to go off at the right time, then perhaps you should disable overnight updates for now, at least until Apple addresses it. Unfortunately it seems that for now there is nothing one can do about it save for disabling the feature until the future.
Alternatively you could always manually install the update which should take several minutes, but if you don’t mind waiting it does seem to be the safer method for now.