Charles Lindsey writes:
Just what you you propose that a type-2 reader should do when it sees this
special header that it would not do if this header was absent?
Here are the two reader strategies that I've mentioned:
(1) Display every 8-bit header field as UTF-8.
(2) Display all the 8-bit header fields in a message as UTF-8 _if_
the message contains the following special header field: ...
Keith has mentioned two more strategies:
(3) Display an 8-bit header field as UTF-8 _if_ it is a valid UTF-8
string.
(4) Display all the 8-bit header fields in a message as UTF-8 _if_
all the fields are valid UTF-8 strings _and_ the message contains
the following special header field: ...
---Dan