[Dovecot] New Dovecot installation and OE not POPing problems

Greetings:

Recently I converted my mailserver to Postfix with some local accounts being accessed via Dovecot and POP3S.

The clients are OE. The users are reporting that they aren't getting their messages. In the past with my old (IW?) POP server, I just used mail -f /var/spool/user and deleted the "DO NOT DELETE THIS MESSAGE...." message #1 and this cleared any problems with messages being out of sync on what had and had not been downloaded, etc.

With Dovecot, I don't know how to "bump" the mailbox to get it "reset" so that OE will download the messages again, and/or get them if it hasn't already. Is this possible?

Thanks very much for the time to help, Scott