POP3 (Post Office Protocol version 3) is the latest version of the Post Office Protocol, a protocol for retrieving email messages from a mail server. It is similar to the original POP protocol, but it includes some additional features and improvements.
POP3 allows a client (such as an email program on a computer or smartphone) to retrieve email messages from a server and download them to the client's device. Like the original POP protocol, POP3 removes the messages from the server after they have been downloaded. However, POP3 includes some additional features that make it more flexible and easier to use than the original POP protocol.
For example, POP3 allows the client to retrieve only the headers of email messages, rather than the entire message, which can save time and bandwidth. It also allows the client to keep messages on the server after they have been downloaded so that the same messages can be accessed from multiple devices.
POP3 is widely used for retrieving email messages from servers, and it is supported by many email programs and web-based email services.