Hello Rob,
If somebody does not want to accept headers with Cyrillic characters,
s/he has to list all character sets allowing Cyrillic characters,
including UTF-8.
OK, I seem to be missing something basic here, but given that a properly
functioning Sieve implementation will decode all encoded words using
well-known charsets to Utf-8, why would you need to list anything other than
the Cyrillic characters as they appear in UTF-8?
Using :regex with a bracket expression covering the entire Cyrillic range in
Unicode (0400-04FF) strikes me as the obvious way to do this.
For me this job is more for a per-user spam filter,
than to Sieve.
I've ignored the question of _why_ you'd want to do this.
Nevertheless, I think that including an option raw in test envelope,
supposes introduction of a similar option in test body,
draft-ietf-sieve-body-07, Section 4.2. ":content".
Again I must be missing something - envelope deals in envelope address
information which is currently restricted to ASCII. Perhaps you meant
the header test instead?
Ned