POP3 vs IMAP
POP3 and IMAP are 2 different methods used to access mail from a third-party email client or software. Review the differences and choose the protocol that's right for your needs. Whether you decide on POP3 or IMAP to access your mail, you'll need to configure the email client with CAS Cable settings.
Difference between POP3 and IMAP
POP3-While it is possible to configure POP3 to keep email data stored on the server, this only applies to email messages. Customizations, like marking an email as read and unread, are not stored on the server and are not synced across devices. However, this configuration is client-specific, so every client you use will need to be configured separately.
IMAP-This synchronizes the emails from the server to the devices and allows more than one device to be synced with the server, since it synchronizes to a device it will copy the mail from the server over instead of downloading and deleting it, this way you can have our email on more than one device.
IMAP is better if you are going to be accessing your email from multiple devices, such as a work computer and a smart phone. POP3 works better if you are only using one device, but have a very large number of emails. It is also better if you have a poor internet connection and need to access your emails offline. For most people, IMAP will suit their needs better.