Re: if you really want utf-8 headers...

> Keith have wondered why we need UTF-8 in headers.

No, that's not what I'm wondering at all.  What I'm wondering is why
people think that merely saying "it's okay to use utf-8 in message
headers" will result in reduced complexity, when even a simple analysis
indicates that it will increase complexity of every part of the mail
system.  And I'm wondering why, given that mail is already getting less
and less useful and less and less reliable due to spam and viruses and
the countermeasures for these, that people think that having unencoded
utf-8 in email addresses is somehow worth making email even less
reliable.  We can provide IMAAs with far less disruption and
transition pain without introducing utf-8 in message headers. 

> If we instead agreed on using a single character set (like UCS) and
> a single transfer encoding on the wire (like UTF-8) things would be
> a lot easier! 

No it wouldn't,  because we're still going to need to accept all of
those various character encodings and ACEs in mail from legacy MUAs and
we're still going to need to accept all of those things in old mail.

But that's part of why I suggested making this change first at the MUA
and message store, without burdening mail transport at least initially -
because the message store is in a good position to convert legacy
messages to the new format, and because POP or IMAP provide the means to
allow simplified MUAs to refuse to deal with legacy messages,
and because it doesn't burden the rest of the mail transport in the near
term.

Keith