Postfix vs Dovecot

[Jos Chrispijn]

[1:24pm] > pkgdb -F
--->  Checking the package registry database
Stale dependency: postfix-2.9.3,1 -> dovecot-1.2.17 (mail/dovecot):

Currently installed:
dovecot-2.1.8       Secure and compact IMAP and POP3 servers
postfix-2.9.3,1     A secure alternative to widely-used Sendmail

Should I now install two versions of Dovecot or do I downgrade either 
Postfix or Dovecot?

kind regards,
Jos Chrispijn