I was looking for a mass mailing function in Microsoft NAV to simplify my work of sending E-mails with PDF attachments to multiple contacts (employees, customers, etc.). If you know any reliable third party add-on, kindly share it too; it will be a great help.
Have a look at “Notification Management” from To-Increase.
this could be made by a customization (little project, about 2-3 days). no need of an external add-on.
if i can help you with that issue, please contact me.