On Thursday, 4th of May 2010, starting at 5pm we will migrate our webmail service to the new mail server. Since there are no version upgrades of the webmail applications Roundcube and Twig, it will be a smooth transition and you shouldn’t even notice the migration. The only thing which can happen is that you get logged out of webmail if you use webmail while the DNS entry changes to the new server address.
Update, Thursday morning: As yesterday morning’s unexpected outage of the old mail server showed further hardware problems, we rescheduled moving the incoming (SMTP) mail server functionality to the new mail server to fit into today’s maintenance window, too.
This will also be done by switching DNS entries, so you should not experience any interruption nor do you need to change any configuration. However this may cause some temporary issues (e.g. delays) since it does involve new software versions as well as new authentication backends.
Update, 22:45: New webmail and incoming mail server seem to work fine, nearly all users already use the new service installation.