IMAP and POP are two different protocols. There are many differences between these two. The main difference is that IMAP(Internet Messaged Access Protocol) always syncs with mail server so that any changes you make in your mail client (Microsoft Outlook, Thunderbird) will instantly appear on your webmail inbox.
On the other hand, in POP(Post Office Protocol), your mail client account and mail server are not synced. It means whatever changes you make to your email account in the mail client will not be transferred to the webmail inbox as the email is deleted from the server since POP fetches the email from your email client.
In simple terms, if you are using IMAP and mark a mail as read, it gets marked as read in your web based inbox too (because the changes are happening on the server). However, this won’t be the case if you are using POP, because the mails are downloaded to your PC and the changes won’t reflect on the server.
With a few rare exceptions, we always recommend IMAP over POP for the following reasons:
- Your emails are synced across all devices.
- There is always a copy of your email on our server, so if anything were to happen to your computer - your email is readily available.