The stock version has the ability to send an email campaign based on a date field in the contact record. The most common use of this feature is to send an email to users on their birthday.
Before you can create the trigger and automate the delivery of email you will of course need to have a date custom field added to your contact list. Call it Birthday or something similar.
Next prepare the email campaign you wish to send to users on their birthday. Like any other email campaign you can include custom fields like first name, last name, etc.
Now for the fun part of setting up the trigger. To set this up first navigate to the “View Triggers” menu under the Autoresponders menu/tab.
Add a new trigger. As seen in the figure below, select the option to activate the trigger based on a custom date field. Select your contact list and the custom date field. Next select the option to send an email campaign and then select the Happy Birthday campaign email that you previously created. Save and activate your trigger.
Make sure your cron settings are configured to run triggers on a regular basis.