Chris Newman wrote: [...]
This approach does not alter: <http://www.ietf.org/internet-drafts/draft-siemborski-rfc2554bis-09.txt> which is in the RFC editor queue.
BTW, this is RFC 4954 now.
One other question: do we want to list one or more non-extended SMTP codes that are typically used with an extended code in the registry?
Speaking as an implementor, I think this would be a really good idea.
