POP3 vs IMAP vs Exchange Connector

POP3

The POP3 protocol, short for Post Office Protocol 3, is the earliest Client-server protocol used for email access by mail programs. In use it copies the email message from the mailserver to the email program on the user’s computer. Then it either sends a delete command for that message to the server, or it waits a few days and then sends the delete command the next time the user checks mail.