pop3-migration plugin

The pop3-migration plugin is used to preserve POP3 UIDLs.

When dsync is handling IMAP INBOX and requests a POP3 UIDL, the plugin connects to the POP3 server and

figures out which IMAP messages match which POP3 messages and then returns the appropriate POP3 UIDL.

See: Migrating from any IMAP/POP3 server to Dovecot via dsync