On Saturday, October 10th I'll be making a significant change to email services on websrv04: migrating the mail server software from QMail+Courier to Postfix+Dovecot, and changing spam and virus protection from MagicSpam to Plesk Email Security Pro.
Mail services will be offline for a short period — under 30 minutes. Your local email client may re-download all messages once the migration is complete.