文章来源：iOS-App版本更新提示
AppDelegate.m文件：

- (void)applicationDidBecomeActive:(UIApplication *)application {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    [[NSNotificationCenter defaultCenter] postNotificationName:@"notification_UpdateAPP" object:self];
}

提示更新的界面增加：

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [self shareAppVersionAlert];//增加版本更新功能
    });
    //软件更新通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(shareAppVersionAlert) name:@"notification_UpdateAPP" object:nil];

#pragma mark 版本更新提示
//判断是否需要提示更新App
- (void)shareAppVersionAlert {
    if(![self judgeNeedVersionUpdate])  return ;
    //App内info.plist文件里面版本号
    NSDictionary *infoDict = [[NSBundle mainBundle] infoDictionary];
    NSString *appVersion = infoDict[@"CFBundleShortVersionString"];
    NSString *AppleID   = @"1382531713";
//    NSString *urlString = [NSString stringWithFormat:@"https://itunes.apple.com/cn/lookup?bundleId=%@", bundleId];//经过测试bundleId获取失败
    NSString *urlString = [NSString stringWithFormat:@"https://itunes.apple.com/cn/lookup?id=%@", AppleID];
    //两种请求appStore最新版本app信息 通过bundleId与appleId判断
    //[NSString stringWithFormat:@"https://itunes.apple.com/cn/lookup?bundleid=%@", bundleId]
    //[NSString stringWithFormat:@"https://itunes.apple.com/cn/lookup?id=%@", appleid]
    NSURL *urlStr = [NSURL URLWithString:urlString];
    //创建请求体
    NSURLRequest *urlRequest = [NSURLRequest requestWithURL:urlStr];
    [NSURLConnection sendAsynchronousRequest:urlRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
        if (connectionError) {
            //            NSLog(@"connectionError->%@", connectionError.localizedDescription);
            return ;
        }
        NSError *error;
        NSDictionary *resultsDict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&error];
        if (error) {
            //            NSLog(@"error->%@", error.localizedDescription);
            return;
        }
        NSArray *sourceArray = resultsDict[@"results"];
        if (sourceArray.count >= 1) {
            //AppStore内最新App的版本号
            NSDictionary *sourceDict = sourceArray[0];
            NSString *newVersion = sourceDict[@"version"];
            if ([self judgeNewVersion:newVersion withOldVersion:appVersion])
            {
//                UIAlertController *alertVc = [UIAlertController alertControllerWithTitle:@"提示:\n您的App不是最新版本，请到App Store进行版本更新" message:@"" preferredStyle:UIAlertControllerStyleAlert];
//                UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
//                    //                    [alertVc dismissViewControllerAnimated:YES completion:nil];
//                }];
//                [alertVc addAction:action1];
                UIAlertController *alertVc = [UIAlertController alertControllerWithTitle:@"提示:\n您的App不是最新版本，请问是否更新" message:@"" preferredStyle:UIAlertControllerStyleAlert];
                UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"暂不更新" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
                    //                    [alertVc dismissViewControllerAnimated:YES completion:nil];
                }];
                [alertVc addAction:action1];
                UIAlertAction *action2 = [UIAlertAction actionWithTitle:@"去更新" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {
                    //跳转到AppStore，该App下载界面
                    if (@available(iOS 10.0, *)) {
                        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:sourceDict[@"trackViewUrl"]] options:@{} completionHandler:^(BOOL success) {
                        }];
                    }else{
                        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:sourceDict[@"trackViewUrl"]]];
                    }
                }];
                [alertVc addAction:action2];
                [self presentViewController:alertVc animated:YES completion:nil];
            }
        }
    }];
}

//每天进行一次版本判断
- (BOOL)judgeNeedVersionUpdate {
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"yyyy-MM-dd"];
    //获取年-月-日
    NSString *dateString = [formatter stringFromDate:[NSDate date]];
    NSString *currentDate = [[NSUserDefaults standardUserDefaults] objectForKey:@"currentDate"];
    if ([currentDate isEqualToString:dateString]) {
        return NO;
    }
    [[NSUserDefaults standardUserDefaults] setObject:dateString forKey:@"currentDate"];
    return YES;
}

//判断当前app版本和AppStore最新app版本大小
- (BOOL)judgeNewVersion:(NSString *)newVersion withOldVersion:(NSString *)oldVersion {
    NSArray *newArray = [newVersion componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"."]];
    NSArray *oldArray = [oldVersion componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"."]];
    for (NSInteger i = 0; i < newArray.count; i ++) {
        if ([newArray[i] integerValue] > [oldArray[i] integerValue]) {
            return YES;
        } else if ([newArray[i] integerValue] < [oldArray[i] integerValue]) {
            return NO;
        } else { }
    }
    return NO;
}