When the download notification feature is enabled, the Add-In will send a private copy of the message to each of the recipients with their own private links so that the Mail Express Server can discern who is downloading a particular file. Due to limitations in Outlook, it is not possible to send these private messages while retaining the original recipient list. To account for this limitation, Mail Express will update the message body to include the original recipient list for these private emails. The updated message body will only occur when the download notification or invitation features are enabled and for emails that are being sent to more than one recipient. The text that is added to emails to support this feature can be customized through a template that resides on the Mail Express Server. Refer to Customizing Mail Express Pages and Notifications for more information.