How To Migrate Mailboxes Between IMAP Servers With IMAP TOOLS

[ Thanks to Falko
for this link. ]

“IMAP TOOLS is a collection of Perl scripts that allow you to do
various tasks with IMAP servers and also POP3 servers. In this
article I will focus on the scripts imapcopy.pl (copies messages
and mailboxes from one IMAP server to another) and pop3toimap.pl
(copies POP3 messages to an IMAP server). Both scripts support SSL.
If you specify port 993 (995 for POP3) then an SSL connection is
initiated. If the port number is 143 (110 for POP3) then it will
try a non-SSL connection. With any other value the port will be
tested to see if it supports SSL. If so, SSL will be used to make
the connection; otherwise a non-SSL connection will be made.”

Complete Story