We've just deployed two fixes to the JangoSMTP transactional email service:
1. Previously, lines in an email message that begin with a single period would result in two periods when delivered to the recipient. This was a bug related to how SMTP treats the escaping of periods. This is now fixed. To read more about issues involving SMTP and periods, see this article: http://db.ilug-bom.org.in/lug-authors/philip/docs/mail-stuff/smtp-intro.html
2. Previously, if an email message was relayed to relay.jangosmtp.net and included both the Disposition-Notification-To and the Return-Receipt-To headers, then JangoSMTP would throw an error on the email message:
System.ArgumentException: An item with the same key has already been added.
This is now fixed, and email messages containing both headers will be delivered properly.