- (BOOL)compareOriginVersion:(NSString *)version  withNewVersion:(NSString *)newVersion{
    
    NSArray *versionArray0 = [version componentsSeparatedByString:@"."];
    NSArray *versionArray1 = [newVersion componentsSeparatedByString:@"."];
    
    NSInteger count = versionArray0.count <= versionArray1.count ? versionArray0.count :versionArray1.count;
    
    for (int i = 0; i < count; i++) {
        NSString *v0 = [versionArray0 objectAtIndex:i];
        NSString *v1 = [versionArray1 objectAtIndex:i];
        if (v0.length > v1.length) {
            return NO;
        }else if(v0.length < v1.length){
            return YES;
        }
        
        if ([v0 compare:v1] == NSOrderedAscending) {
            return YES;
        }else if ([v0 compare:v1] == NSOrderedDescending){
            return NO;
        }
    }
    
    if (versionArray0.count > versionArray1.count) {
        return NO;
    }else{
        return YES;
    }
}

利用iTunes接口检查App版本更新

/// 检查版本更新
- (void)checkVersion {
    NSURL * url = [NSURL URLWithString:@"http://itunes.apple.com/lookup?id=414478124"];
    [[[NSURLSession sharedSession] dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        NSDictionary * dataDic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
        NSArray *results = dataDic[@"results"];
        if (results && results.count > 0) {
            NSDictionary *response = results.firstObject;
            NSString *currentVersion = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"]; // 软件的当前版本
            NSString *lastestVersion = response[@"version"]; // AppStore 上软件的最新版本
            if (currentVersion && lastestVersion && ![self isLastestVersion:currentVersion compare:lastestVersion]) {
                NSString * releaseNotes = response[@"releaseNotes"]; // 新版本更新内容
                NSString * alertContent = [NSString stringWithFormat:@"%@\n\n是否前往 AppStore 更新版本？",releaseNotes];
                // 给出提示是否前往 AppStore 更新
                UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"检测到有版本更新" message:alertContent preferredStyle:UIAlertControllerStyleAlert];
                [alert addAction:[UIAlertAction actionWithTitle:@"前往" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
                    NSString *trackViewUrl = response[@"trackViewUrl"]; // AppStore 上软件的地址
                    if (trackViewUrl) {
                        NSURL *appStoreURL = [NSURL URLWithString:trackViewUrl];
                        if ([[UIApplication sharedApplication] canOpenURL:appStoreURL]) {
                            [[UIApplication sharedApplication] openURL:appStoreURL];
                        }
                    }
                }]];
                [alert addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil]];
                [[UIApplication sharedApplication].keyWindow.rootViewController presentViewController:alert animated:YES completion:nil];
            }
        }
    }] resume];
}


/// 判断是否最新版本号（大于或等于为最新）
- (BOOL)isLastestVersion:(NSString *)currentVersion compare:(NSString *)lastestVersion {
    if (currentVersion && lastestVersion) {
        // 拆分成数组
        NSMutableArray *currentItems = [[currentVersion componentsSeparatedByString:@"."] mutableCopy];
        NSMutableArray *lastestItems = [[lastestVersion componentsSeparatedByString:@"."] mutableCopy];
        // 如果数量不一样补0
        NSInteger currentCount = currentItems.count;
        NSInteger lastestCount = lastestItems.count;
        if (currentCount != lastestCount) {
            NSInteger count = labs(currentCount - lastestCount); // 取绝对值
            for (int i = 0; i < count; ++i) {
                if (currentCount > lastestCount) {
                    [lastestItems addObject:@"0"];
                } else {
                    [currentItems addObject:@"0"];
                }
            }
        }
        // 依次比较
        BOOL isLastest = YES;
        for (int i = 0; i < currentItems.count; ++i) {
            NSString *currentItem = currentItems[i];
            NSString *lastestItem = lastestItems[i];
            if (currentItem.integerValue != lastestItem.integerValue) {
                isLastest = currentItem.integerValue > lastestItem.integerValue;
                break;
            }
        }
        return isLastest;
    }
    return NO;
}