skyaptnotify is a little program which sends mail to OpenGroupware.org
users to notify them for upcoming appointments (if they selected to be
notified).

skyaptnotify must be called regularily by cron to work. It is suggested
to add an entry into the crontab of the user which runs the
OpenGroupware.org daemon (usually user ogo):

Become root
$ su - ogo
$ crontab -e
Add the following to the opening crontab file:
0-59/5 * * * * /usr/bin/skyaptnotify >/dev/null 2>> /var/log/opengroupware.org/ogo/skyaptnotify.log

That will check for upcoming appointments every five minutes and send
out he appropriate emails.