An interesting question has come up during internal discussions of MIME.
I do not recall it being discussed here nor can I find any reference to
it in the document. If I'm overlooking something please just let me
Are there any rules regarding the "inheritance" of content transfer
encodings (CTE)? For example, suppose a terminal (non-recursive body
part) CTE is 8bit. Can the CTE for an enclosing type be 7bit?
There seems to be an implicit ordering of the CTE types, probably
binary > 8bit > 7bit > quoted-string > base64
This suggests that there could be two rules:
o enclosing, recursive CTEs have to be at least as "big" as all
of the enclosed CTEs
o the least level for a recursive CTE is 7bit
To put forth a particular example, is there anything to prevent a
top-level message from having:
and having one of the body parts have:
C-T: image [or something else]