I'm looking into using Dovecot as a way to store all my old emails (I have emails going back 20 years would you believe!)
Before I commit to it though, I am testing how easy it is to migrate between servers.
To import the contents of one Maildir into Dovecot, use the following:
doveadm -Dv import maildir:<path> "" all
-Dvmeans verbose debugging. You don't need that.
maildir:<path>tells Dovecot where to get the emails from, and that they're in the Maildir format.
""is the root folder that the messages should be imported into. In this case, it's the actual root, so the folder structure should be identical to the source.
allis the search query. In this case, import all of them.