[Dovecot] Script to convert mboxes to maildirs?

Does anybody know of a script of a simple method of converting mbox mail stores to maildirs? I'm moving from an old pop3 system to imap and after installing about half our office with mboxes have found that mbox does not support subfolders which some people like to use.

Is there any simple way of converting? I can go to each individual account and "manually" convert swaping data around with Firefox, but I was wondering if there was an easier way.

Thanks.

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