2.2 MIME Analysis Algorithm Details
This section specifies both conversion from pure MIME messages to Message objects, and from TNEF messages to Message objects. The agent that performs the conversion is referred to as a MIME reader for clarity, because both clients and servers perform this conversion for different protocols.
As a general rule, when data occurs both in MIME format and in a TNEFbody part, the version found in MIME format SHOULD<107> be preferred. The message body is an exception to this rule: the plain text rendering found in MIME messages SHOULD NOT be used in preference to a richer (HTML or RTF) rendering found in TNEF messages. As an implementation guideline, MIME readers can process the TNEF body part before processing the remaining MIME data so that data from the MIME message overwrites the conflicting data from the TNEF message.