It allows mail-processing agents (such as a POPserver) to distinguish between mail messages that are generated by older versions and new versions.
它应用邮件处理代理(例如一个POP服务器)来区别旧版本和新版本所生成的邮件消息。
2
Moreover, the password needed for authentication is also transmitted as plaintext when a connection to POPserver is established, which may result in the stealing and divulging of the email.