NSString *str = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"];

    NSString *isForst = [[NSUserDefaults standardUserDefaults] objectForKey:@"CFBundleShortVersionString"];

    NSUserDefaults *use = [NSUserDefaults standardUserDefaults];

    if (isForst.length == 0) {

        NSLog(@"第一次啟動(dòng)");

        [use setObject:str forKey:@"CFBundleShortVersionString"];

        [use synchronize];

    }

    else if ([str isEqualToString:isForst]) {

        NSLog(@"沒(méi)有升級(jí)");

    } else {

            NSLog(@"升級(jí)");

            [use setObject:str forKey:@"CFBundleShortVersionString"];

            [use synchronize];

    }