You can also setup the addon so that attendees (or all registered users) are auto reminded before events.
You configure the addon to set the lead time before the event that you want the reminder to be sent and a server crontab job/scheduled task sends the messages at the appropriate time.
You can also customise the reminder message that is sent on an event-by-event basis.
Note that the screenshots above feature a new experimental SMS plugin that allows reminders to be sent via SMS. This is a new feature and needs a special plugin to be written for each SMS gateway - if a new gateway is required we may need to charge for the cost of its development.
A demo video of this functionality is available.