126.96.36.199 MIME Conversion
During MIME conversion, the MIME reader keeps track of which MIME parts are saved as attachments and which MIME part is promoted as the message body. If any of these MIME parts are missing a Content-Idheader (2), the MIME reader generates an X-Exchange-MIME-Skeleton-Content-Id header (2) and promotes it to the PidTagBodyContentId property ([MS-OXCMSG] section 188.8.131.52.7) or the PidTagAttachContentId property ([MS-OXCMSG] section 184.108.40.206) as appropriate. If the message did not have a TNEF MIME part, or it was not promoted, after the message is converted, the whole MIME message SHOULD be saved in the PidTagMimeSkeleton property ([MS-OXCMSG] section 220.127.116.11), with the MIME part content filtered out for MIME parts that were promoted as a message attachment or message body.
If the message body was an aggregate body, as specified in section 18.104.22.168.2.2, MIME readers SHOULD NOT set the PidTagMimeSkeleton property.
Body part contents for the following content types are included in the PidTagMimeSkeleton property even when the MIME reader has copied their contents to the Message object.
iCalendar MIME parts are not filtered out of the PidTagMimeSkeleton property.
For S/MIME messages, the PidTagMimeSkeleton property contains only root part headers (2) since the rest of the data can be retrieved from the attachment.
For DSN messages, an original message attachment is filtered out only if it was promoted as an attachment. Human-readable body content is always filtered. Report parts, which are specified in [RFC3464] as message parts with a Content-Type header (2) value of "message/delivery-status", are not filtered out.