I Found the problem. Apparently to use iBeacons in the way that is described in the documents users are required to have the Background Refresh setting enabled in the Settings. To check for this setting I use the following snippet:
if ([[UIApplication sharedApplication] backgroundRefreshStatus] == UIBackgroundRefreshStatusAvailable) {
NSLog(@"Background updates are available for the app.");
}else if([[UIApplication sharedApplication] backgroundRefreshStatus] == UIBackgroundRefreshStatusDenied)
{
NSLog(@"The user explicitly disabled background behavior for this app or for the whole system.");
}else if([[UIApplication sharedApplication] backgroundRefreshStatus] == UIBackgroundRefreshStatusRestricted)
{
NSLog(@"Background updates are unavailable and the user cannot enable them again. For example, this status can occur when parental controls are in effect for the current user.");
}
Found in this answer: Detecting user settings for Background App Refresh in iOS 7