Moreover, interim servers between the recaller and the recipient can be any version because the request at that point is simply an email message.

此外，收件人和发件人之间的中间服务器可以是任意版本的服务器，因为此时的请求只是一个电子邮件消息。

youdao

Moreover, interim servers between the recaller and the recipient can be any version because the request at that point is simply an email message.

此外，收件人和发件人之间的中间服务器可以是任意版本的服务器，因为此时的请求只是一个电子邮件消息。

youdao