This afternoon, I browsed the e-mail and saw a mail "Debian GNU/Linux 3.1 updated" and thought "I should do that upgrade of the home server gosper to the current stable anyway, let's start it now". So I did, worked out all the problems associated with the upgrade (sendmail only broke a tiny bit, inn2 needed major whacking before it was running again, the usual). Right after I finished the upgrade and started looking whether mail was flowing, I saw the mail "Debian GNU/Linux 4.0 released" .. that previous mail only mentioned "upcoming release".