Restoring the emails from old server
Think before do it!!
If the users are using mail client to access emails, rather than webmail, this would be a big over head for them. If we copy all mails from old server to new server, email clients will start to download all messages as it was configured newly. Think of email account those having 1 GB of email.
Any way, if we wish to put them on the new server, the solution is simple. Just copy the email folders from old server to new server.
My Maildir structure on old server was similar to below.
Maildir in my new server is similar to below format
Only what we have to do is, examine target directory structure and change the source to match it. Then replace the directories of each user in the target server. That’s all.