A New Internet-Draft is available from the on-line Internet-Drafts directories.
Abstract: “Recent discussions have shown that it is desirable to set different IMAP flags on message delivery. This can be done, for example, by a Sieve interpreter that works as a part of a Mail Delivery Agent.
This document describes an extension to the Sieve mail filtering language for setting IMAP flags. The extension allows to set both IMAP system flags and IMAP keywords.”
http://www.ietf.org/internet-drafts/draft-melnikov-sieve-imapflags-06.txt