How can be sure of the current POP3 UIDL?

Below my current config (to be migrated to 2.0.x ASAP).

Thanks, P.

# dovecot -n # 1.0.2: /etc/dovecot.conf log_path: /var/log/mail/dovecot.log info_log_path: /var/log/mail/dovecot.info.log protocols: pop3 pop3s imap imaps listen: * login_dir: /var/run/dovecot/login login_executable(default): /usr/libexec/dovecot/imap-login login_executable(imap): /usr/libexec/dovecot/imap-login login_executable(pop3): /usr/libexec/dovecot/pop3-login first_valid_uid: 100 mail_location: mbox:~/:INBOX=/var/mail/%u mail_full_filesystem_access: yes mbox_read_locks: dotlock fcntl mbox_write_locks: dotlock fcntl mail_executable(default): /usr/libexec/dovecot/imap mail_executable(imap): /usr/libexec/dovecot/imap mail_executable(pop3): /usr/libexec/dovecot/pop3 mail_plugin_dir(default): /usr/lib/dovecot/imap mail_plugin_dir(imap): /usr/lib/dovecot/imap mail_plugin_dir(pop3): /usr/lib/dovecot/pop3 auth default: passdb: driver: pam userdb: driver: passwd