To set the value of the PidTagBodyContentId property ([MS-OXCMSG] section, clients MUST write the value to a Content-ID header on a MIME entity that maps to a message body, as specified in section If this value starts with "<" (U+003C) and/or ends with ">" (U+003E), these characters SHOULD be removed. Leading and trailing whitespace characters SHOULD also be removed.

MIME readers SHOULD<135> copy the value of a Content-ID header on such a MIME entity to the value of the PidTagBodyContentId property.

Clients can write either a Content-ID or a Content-Location header, but SHOULD NOT write both on a single MIME entity.