I am running an old windows mailserver. Several mail accounts use imap with more or less complex folder structure. These imap accounts should be moved (copied) to a new ISPConfig system, so the on the new system the user gets the same folder structure than he had on the old system. Ideally the user should not even notice that there was a change. I have set up a mailproxy in front of the mailservers so that I can easily switch from one server to the other (I am able to set the logins on the new system the same as on the old system). I am thinking about two solutions: Setup the new account in ISPConfig and use the fetchmail function from ISPConfig => this needs a special getmail configuration, so that all folders are pulled and the mails are put to the maildir directly without parsing. How do I make this getmail configuration? (type = Maildir, mailboxes = ALL, ????) Use a Mailclient like Thunderbird, configure the old mailbox and pull everything to thunderbird, then change the configuration to the new mailbox. => Do I need to add both mailboxes to Thunderbird and then copy everything from one account to the other by hand or will it be enough when I just change the servername in the account configuration? (first configure the "oldServer", pull everything, then just change configuration to "newServer" and hopefully it will push everything from Thunderbird to the new server). What would you recommend? Just to be clear: my aim is, that the user does not need to do something on this side!