> > However, this raises a question: does *anyone* use external-body in > > association with I-D announcements? > > Several MUAs support message/external-body, but they don't all work with > the I-D announcements. Specifically, some MUAs only render the entities if > a Content-Transfer-Encoding MIME header field is defined, How bizarre. You mean those MUAs can default to 7bit for other bodyparts but not for message/external-body? And that multiple implementors have made this same error? > Even though fixing the MUAs would be the best fix in the long-term, adding > the CTE MIME header field to these entities would at least allow more MUAs > to render the entities appropriately. Since this is a mandatory header > field for some entities, there is some argument that the missing CTE is > the problem anyway. The RFC is quite clear that in the absence of a content-transfer-encoding field it is interpreted as 7bit. And while for some types it is a practical necessity (try encoding a JPEG image using only octets between 0x01-0x7f with 0x0d 0x0a pairs every 80 or so octets) as far as the MIME standards are concerned it's not mandatory for any kind of body part. Certainly it's not needed for message/external-body. But I do think it would be an interesting experiment to add the line content-transfer-encoding: 7bit to the external body parts of those notices, just to see how many more MUAs worked with them. Keith