MyAppDelegate.m

if ([[UIApplication sharedApplication] respondsToSelector:@selector(registerUserNotificationSettings:)]) {
    UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:(UIUserNotificationTypeAlert | UIUserNotificationTypeBadge | UIRemoteNotificationTypeSound) categories:nil];
    [[UIApplication sharedApplication] registerUserNotificationSettings:settings]; // Asks users for authorization
    [[UIApplication sharedApplication] registerForRemoteNotifications];
} else {
    [[UIApplication sharedApplication] registerForRemoteNotificationTypes:(UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound)]; // Asks users for authorization
}