It looks like Maildir (or at least Courier) gets its mail received time
stamp from the time on the file itself. For most things this doesn't
matter, even with my wholesale moving of messages, but for at least one
user it really does matter. So, before I move all their mbox-based mail
to Maildirs, how do I preserve the received time stamp that will show up
in their MUA?
This was addressed already earlier in the thread.
procmail mailing list Procmail homepage: http://www.procmail.org/