Я хочу вызватьUILocalNotification однако каждое воскресенье в 8 часов вечера у меня выходной день в 8 часов вечера.

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDate *now = [NSDate date];
    NSDateComponents *componentsForFireDate = [calendar components:(NSYearCalendarUnit |   NSHourCalendarUnit | NSMinuteCalendarUnit| NSSecondCalendarUnit | NSWeekdayCalendarUnit) fromDate: now];
    [componentsForFireDate setWeekday: 1] ; //for fixing Sunday
    [componentsForFireDate setHour: 20] ; //for fixing 8PM hour
    [componentsForFireDate setMinute:0] ;
    [componentsForFireDate setSecond:0] ;

    NSDate *fireDateOfNotification = [calendar dateFromComponents: componentsForFireDate];
    UILocalNotification *notification = [[UILocalNotification alloc]  init] ;
    notification.fireDate = fireDateOfNotification ;
    notification.timeZone = [NSTimeZone localTimeZone] ;
    notification.alertBody = [NSString stringWithFormat: @"New updates!"] ;
    notification.userInfo= [NSDictionary dictionaryWithObject:[NSString stringWithFormat:@"New updates added for that week!"] forKey:@"new"];
    notification.repeatInterval= NSDayCalendarUnit ;
    notification.soundName=UILocalNotificationDefaultSoundName;

    NSLog(@"notification: %@",notification);//it indicates that the notif will be triggered today at 8PM and not Sunday.

    [[UIApplication sharedApplication] scheduleLocalNotification:notification] ;

Спасибо.