MailBee.NET Objects currently does not understand the top level Content-Type container of "multipart/report". This multipart container allows reports on previously sent messages. It reports useful information in both a human and machine readable format that, among other purposes, allows mail user agents to keep track of the disposition of sent messages and convey message disposition notifications (MDNs, RFC 3798) between mail gateways.

MailBee.NET objects do not currently support the creation of MDNs. It rewrites existing messages as “multipart/mixed” if an MDN needs to be recreated due to change in message data. Support of “multipart/report” MDNs will allow for standards compliant adherence when implementing SMTP workflow messages such as Read Receipts. As the MIME structure continues to evolve, reliable delivery will become of greater importance. Support for reliable delivery is already a required part of certain extended protocols. A prominent example is the US federal government requirement for implementation of the Direct protocol for health information exchange (RFC 5322 + S/MIME). The US government requires another level of receipt verification beyond standard SMTP status codes for the exchange of protected healthcare information using Direct. Please refer to the US federal government website www.healthit.gov and wiki.directproject.org.

Desired functionality would be to allow the top level content type to be set to “multipart/report” and to respect the media type when rebuilding existing messages. Additionally, body part media type headers (particular the machine readable 2nd body party) should be settable and respected if they are not already. Without such functionality, Mailbee cannot be used in SMTP messaging environments regulated by the US federal government.