Skip to main content

5. Overview of the Approach and Document Plan

This set of specifications changes both SMTP and the character encoding of email message headers to permit non-ASCII characters to be represented directly. Each important component of the work is described in a separate document. The document set, whose members are described below, also contains Informational documents whose purpose is to provide implementation suggestions and guidance for the protocols.

In addition to this document, the following documents make up this specification and provide advice and context for it.

  • SMTP extension. The SMTP extension document [RFC6531] provides an SMTP extension (as provided for in RFC 5321) for internationalized addresses.

  • Email message headers in UTF-8. The email message header document [RFC6532] essentially updates RFC 5322 to permit some information in email message headers to be expressed directly by Unicode characters encoded in UTF-8 when the SMTP extension described above is used. This document, possibly with one or more supplemental ones, will also need to address the interactions with MIME, including relationships between SMTPUTF8 and internal MIME headers and content types.

  • Extensions to delivery status and notification handling to adapt to internationalized addresses [RFC6533].

  • Forthcoming documents will specify extensions to the IMAP protocol [RFC3501] to support internationalized message headers [RFC5738bis-IMAP], parallel extensions to the POP protocol [RFC5721] [RFC5721bis-POP3], and some common properties of the two [POPIMAP-downgrade].