[Dovecot] migrating POP3 from UW IMAP: X-UIDL and X-UID

With a INBOX mbox created by UW IMAP

the messages in INBOX mbox contains the X-UIDL field

When I use Dovecot POP3 with

pop3_uidl_format = %08Xv%08Xu

on the first run, X-UID is inserted, but all messages are downloaded again.

What am I missing, I don't want the clients to download the read messages again.

Thanks

Bertrand Leboeuf leboeuf@emt.inrs.ca