Post-Delivery Message Downgrading for Internationalized Email Messages
Draft of message to be sent after approval:
From: The IESG <firstname.lastname@example.org> To: IETF-Announce <email@example.com> Cc: RFC Editor <firstname.lastname@example.org>, eai mailing list <email@example.com>, eai chair <firstname.lastname@example.org> Subject: Protocol Action: 'Post-delivery Message Downgrading for Internationalized Email Messages' to Proposed Standard (draft-ietf-eai-popimap-downgrade-08.txt) The IESG has approved the following document: - 'Post-delivery Message Downgrading for Internationalized Email Messages' (draft-ietf-eai-popimap-downgrade-08.txt) as Proposed Standard This document is the product of the Email Address Internationalization Working Group. The IESG contact persons are Pete Resnick and Barry Leiba. A URL of this Internet Draft is: http://datatracker.ietf.org/doc/draft-ietf-eai-popimap-downgrade/
[Please note: This document is one a set of four interdependent documents: draft-ietf-eai-5738bis draft-ietf-eai-popimap-downgrade draft-ietf-eai-rfc5721bis draft-ietf-eai-simpledowngrade These documents should be reviewed, evaluated, and understood together.] Technical Summary The Email Address Internationalization (SMTPUTF8) extension to SMTP allows UTF-8 characters in mail header fields. Upgraded POP and IMAP servers support internationalized Email messages. If a POP/IMAP client does not support Email Address Internationalization, POP/IMAP servers cannot deliver Internationalized Email Headers to the client and cannot remove the message. To avoid the situation, this document describes a conversion mechanism for internationalized Email messages to be in traditional message format. In the process, message elements requiring internationalized treatment are recoded or removed and receivers are able to know that they received messages containing such elements even if they cannot process the internationalized elements. Working Group Summary No particular process issues of note. The WG had extensive and constructive discussions about the role of "downgrading" (e.g., converting a message stored on the server that contains non-ASCII header or envelope information) in the transition to an all-i18n environment. Some of those issues and tradeoffs are discussed in draft-ietf-eai-popimap-downgrade and draft-ietf-eai-simpledowngrade. In some cases, the best strategy may be to "hide" those messages that cannot be delivered without change to legacy clients either with or without some attempt at an error message. A complete treatment of those options is impossible because the optimal strategies will depend considerably on local circumstances. Consequently the base IMAP and POP3 documents are no longer dependent on particular downgrading choices and that two methods presented are, to a considerable extent, just examples. They are recommended as alternative Standards Track documents because they are protocol specifications and their sometimes-subtle details have have been carefully worked out, even though the WG has no general recommendation to make between them (or other strategies). While opinions differ in the WG about which downgrading mechanisms are likely to see the most use, if any, consensus is strong that these four documents represent the correct output. Document Quality Some development and interoperability testing has occurred and is progressing. There are strong commitments in various countries to implement and deploy the EAI (more properly, SMTPUTF8) messages and functions specified in RFCs 6530 through 6533. Those messages will be inaccessible to many users without POP3 and IMAP support, so these specifications are quite likely to be implemented and deployed in a timely fashion. Reviewers who made particular contributions prior to IETF Last Call are acknowledged in the documents. See Section 3 for additional information. Personnel Document Shepherd: John C Klensin Responsible Area Director: Pete Resnick RFC Editor Note OLD This procedure may generate empty <group> elements in "From:", "Sender:" and "Reply-To:" header fields. [I-D.leiba-5322upd-from-group] updates [RFC5322] to allow (empty) <group> elements in "From:", "Sender:" and "Reply-To:" header fields. NEW This procedure may generate empty <group> elements in "From:", "Sender:" and "Reply-To:" header fields. [I-D.leiba-5322upd-from-group] updates [RFC5322] to allow (empty) <group> elements in "From:" and "Sender:".