If you use an alarm clock app, do not update the app.

Due to some changes related to iOS, the new version of "iHome + Sleep" will not activate your alarm unless the app is running in the foreground and you have not manually locked the device. The developers are currently working to fix this issue. I assume developers of other alarm clock apps have also released new versions in which the developer(s) removed this feature. Therefore, I advise all users of alarm clock apps to refrain from updating their apps unless they are absolutely certain that the developer(s) has/have not removed this feature.

 

When the developer of your app decides to release an update that removes this feature. I think it doesn't work because of Apple. Now, I have iOS 6.1.3, the latest iOS version, and I did not update the app, I still have the feature.

The app's page says "What's new: -Bug fixes and changes in order to meet iOS compliance...iHome + Sleep must now be running in the foreground. **Do not lock your iOS device or otherwise put it in the background before you go to sleep.**" I assume this means Apple changed a rule.

I don't know any other apps that don't have this feature. To see if an app has this feature, set an alarm, then lock your device. Make sure you should be able to hear the alarm. Do not unlock the device until the alarm time has passed.