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Use of Internationalized Email Addresses in the Extensible Provisioning Protocol (EPP)
draft-ietf-regext-epp-eai-20

Document Type Active Internet-Draft (regext WG)
Authors Dmitry Belyavsky , James Gould
Last updated 2024-03-20 (Latest revision 2023-11-06)
Replaces draft-belyavskiy-epp-eai
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Submit for publication "Use of Internationalized Email Addresses in EPP protocol"
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draft-ietf-regext-epp-eai-20
Network Working Group                                      D. Belyavskiy
Internet-Draft                                                          
Intended status: Standards Track                                J. Gould
Expires: 9 May 2024                                       VeriSign, Inc.
                                                         6 November 2023

Use of Internationalized Email Addresses in the Extensible Provisioning
                             Protocol (EPP)
                      draft-ietf-regext-epp-eai-20

Abstract

   This document describes an EPP command-response extension that
   permits usage of Internationalized Email Addresses in the EPP
   protocol and specifies the terms when it can be used by EPP clients
   and servers.  The Extensible Provisioning Protocol (EPP), being
   developed before the standards for SMTPUTF8 compliant addresses, does
   not support such email addresses.

   TO BE REMOVED on turning to RFC: The document is edited in the
   dedicated github repo (https://github.com/beldmit/eppeai).  Please
   send your submissions via GitHub.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 9 May 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Conventions Used in This Document . . . . . . . . . . . .   4
   2.  Migrating to Newer Versions of This Extension . . . . . . . .   4
   3.  Email Address Specification . . . . . . . . . . . . . . . . .   5
   4.  SMTPUTF8 <eai:eai> Element  . . . . . . . . . . . . . . . . .   5
   5.  SMTPUTF8 Extension  . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Scope of Extension  . . . . . . . . . . . . . . . . . . .   6
     5.2.  Signaling Client and Server Support . . . . . . . . . . .   6
     5.3.  Extension Behavior  . . . . . . . . . . . . . . . . . . .   6
       5.3.1.  SMTPUTF8 compliant addresses Extension Negotiated . .   6
       5.3.2.  SMTPUTF8 Extension Not Negotiated . . . . . . . . . .   7
   6.  EPP Command Mapping . . . . . . . . . . . . . . . . . . . . .   8
     6.1.  EPP Query Commands  . . . . . . . . . . . . . . . . . . .   8
       6.1.1.  EPP <check> Command . . . . . . . . . . . . . . . . .   8
       6.1.2.  EPP <info> Command  . . . . . . . . . . . . . . . . .   8
       6.1.3.  EPP <transfer> Query Command  . . . . . . . . . . . .  12
     6.2.  EPP Transform Commands  . . . . . . . . . . . . . . . . .  13
       6.2.1.  EPP <create> Command  . . . . . . . . . . . . . . . .  13
       6.2.2.  EPP <delete> Command  . . . . . . . . . . . . . . . .  16
       6.2.3.  EPP <renew> Command . . . . . . . . . . . . . . . . .  16
       6.2.4.  EPP <transfer> Command  . . . . . . . . . . . . . . .  16
       6.2.5.  EPP <update> Command  . . . . . . . . . . . . . . . .  16
   7.  Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . .  18
     7.1.  SMTPUTF8 Addresses Schema . . . . . . . . . . . . . . . .  18
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
     8.1.  XML Namespace . . . . . . . . . . . . . . . . . . . . . .  19
     8.2.  EPP Extension Registry  . . . . . . . . . . . . . . . . .  20
   9.  Implementation Status . . . . . . . . . . . . . . . . . . . .  20
     9.1.  Verisign EPP SDK  . . . . . . . . . . . . . . . . . . . .  20
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  21
   11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  22
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  22
     12.2.  Informative References . . . . . . . . . . . . . . . . .  23
   Appendix A.  Change History . . . . . . . . . . . . . . . . . . .  23
     A.1.  Change from 00 to 01  . . . . . . . . . . . . . . . . . .  23
     A.2.  Change from 01 to 02  . . . . . . . . . . . . . . . . . .  23

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     A.3.  Change from 02 to 03  . . . . . . . . . . . . . . . . . .  24
     A.4.  Change from 03 to 04  . . . . . . . . . . . . . . . . . .  24
     A.5.  Change from 04 to the regext 01 version . . . . . . . . .  24
     A.6.  Change from the regext 01 to regext 02 version  . . . . .  24
     A.7.  Change from the regext 02 to regext 03 version  . . . . .  24
     A.8.  Change from the regext 03 to regext 04 version  . . . . .  24
     A.9.  Change from the regext 04 to regext 05 version  . . . . .  24
     A.10. Change from the regext 05 to regext 06 version  . . . . .  25
     A.11. Change from the regext 06 to regext 07 version  . . . . .  25
     A.12. Change from the regext 07 to regext 08 version  . . . . .  25
     A.13. Change from the regext 08 to regext 09 version  . . . . .  25
     A.14. Change from the regext 09 to regext 10 version  . . . . .  25
     A.15. Change from the regext 10 to regext 11 version  . . . . .  25
     A.16. Change from the regext 11 to regext 12 version  . . . . .  25
     A.17. Change from the regext 12 to regext 13 version  . . . . .  25
     A.18. Change from the regext 13 to regext 14 version  . . . . .  25
     A.19. Change from the regext 14 to regext 15 version  . . . . .  26
     A.20. Change from the regext 15 to regext 16 version  . . . . .  26
     A.21. Change from the regext 16 to regext 17 version  . . . . .  26
     A.22. Change from the regext 17 to regext 18 version  . . . . .  26
     A.23. Change from the regext 18 to regext 19 version  . . . . .  26
     A.24. Change from the regext 19 to regext 20 version  . . . . .  26
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  26

1.  Introduction

   [RFC6530] introduced the framework for Internationalized Email
   Addresses.  To make such addresses more widely accepted, the changes
   to various protocols need to be introduced.

   This document describes an Extensible Provisioning Protocol (EPP)
   command-response extension, defined in [RFC5730], that permits the
   usage of Internationalized Email Addresses in the EPP protocol,
   specifies the terms when it can be used by EPP clients and servers,
   and defines an alternate email to use from ASCII-only to both ASCII
   and SMTPUTF8.  The extension is used to apply the rules for the
   processing of email address elements in all of the [RFC5730]
   extensions negotiated in the EPP session, which include the object
   and command-responses extensions.  The extension can be applied to
   any object or command-response extension that uses an email address.

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   The Extensible Provisioning Protocol (EPP) specified in [RFC5730] is
   a base document for object management operations and an extensible
   framework that maps protocol operations to objects.  The specifics of
   various objects managed via EPP is described in separate documents.
   This document is only referring to an email address as a property of
   a managed object, such as the <contact:email> element in the EPP
   contact mapping [RFC5733] or the <org:email> element in the EPP
   organization mapping [RFC8543], and command-response extensions
   applied to a managed object.

1.1.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   XML is case sensitive.  Unless stated otherwise, XML specifications
   and examples provided in this document MUST be interpreted in the
   character case presented in order to develop a conforming
   implementation.

   In examples, "C:" represents lines sent by a protocol client and "S:"
   represents lines returned by a protocol server.  Indentation and
   white space in the examples are provided only to illustrate element
   relationships and are not REQUIRED in the protocol.

   The XML namespace prefix "eai" is used for the namespace
   "urn:ietf:params:xml:ns:epp:eai-1.0", but implementations MUST NOT
   depend on it and instead employ a proper namespace-aware XML parser
   and serializer to interpret and output the XML documents.

2.  Migrating to Newer Versions of This Extension

   Servers that implement this extension SHOULD provide a way for
   clients to progressively update their implementations when a new
   version of the extension is deployed.  A newer version of the
   extension is expected to use an XML namespace URI with a higher
   version number than the prior versions.

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3.  Email Address Specification

   Support of non-ASCII email address syntax is defined in RFC 6530
   [RFC6530].  This mapping does not prescribe minimum or maximum
   lengths for character strings used to represent email addresses.  The
   exact syntax of such addresses is described in Section 3.3 of
   [RFC6531].  The validation rules introduced in RFC 6531 MUST be
   followed when processing this extension.

   The definition of email address in the EPP RFCs, including
   Section 2.6 of [RFC5733] and Section 4.1.2, 4.2.1, and 4.2.5 of
   [RFC8543], references [RFC5322] for the email address syntax.  The
   XML schema definition in Section 4 of [RFC5733] and Section 5 of
   [RFC8543] defines the "email" element using the type
   "eppcom:minTokenType", which is defined in Section 4.2 of [RFC5730]
   as an XML schema "token" type with minimal length of one.  The XML
   schema "token" type will fully support the use of SMTPUTF8 compliant
   addresses so the primary application of the extension is to apply the
   use of [RFC6531] instead of [RFC5322] for the email address syntax.
   Other EPP extensions may follow the formal syntax definition using
   the XML schema type "eppcom:minTokenType" and the [RFC5322] format
   specification, where this extension applies to all EPP extensions
   with the same or similar definitions.

   The email address format is formally defined in Section 3.4.1 of
   [RFC5322], which only consists of printable US-ASCII characters for
   both the local-part and the domain ABNF rules.  [RFC6531] extends the
   Mailbox, Local-part and Domain ABNF rules in [RFC5321] to support
   "UTF8-non-ascii", defined in Section 3.1 of [RFC6532], for the local-
   part and U-label, defined in Section 2.3.2.1 of [RFC5890], for the
   domain.  By applying the syntax rules of [RFC6531], the EPP
   extensions will change from supporting only ASCII characters to
   supporting Internationalized characters both in the email address
   local-part and domain-part.

4.  SMTPUTF8 <eai:eai> Element

   An alternate email can be set using the <eai:eai> element with the
   command and response extensions defined in Section 6.  The <eai:eai>
   element contains the following child element:

   <eai:email>:  An element following the syntax in Section 3 for
       defining an alternate ASCII or SMTPUTF8 address.  An empty
       <eai:email/> element unsets the alternate email in the Update
       Command (Section 6.2.5) and indicates the alternate email is not
       set in the Info Response (Section 6.1.2).

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5.  SMTPUTF8 Extension

5.1.  Scope of Extension

   The extension applies to all object extensions and command-response
   extensions negotiated in the EPP session that include email address
   properties.  Examples include the <contact:email> element in the EPP
   contact mapping [RFC5733] or the <org:email> element in the EPP
   organization mapping [RFC8543].  All registry zones (e.g., top-level
   domains) authorized for the client in the EPP session apply.  There
   is no concept of a per-client, per-zone, per-extension, or per-field
   setting that is used to indicate support for SMTPUTF8 compliant
   addresses, but instead it's a global setting that applies to the EPP
   session.

5.2.  Signaling Client and Server Support

   The client and the server can signal support for the extension using
   a namespace URI in the login and greeting extension services
   respectively.  The namespace URI "urn:ietf:params:xml:ns:epp:eai-1.0"
   is used to signal support for the extension.  The client includes the
   namespace URI in an <svcExtension> <extURI> element of the [RFC5730]
   <login> Command.  The server includes the namespace URI in an
   <svcExtension> <extURI> element of the [RFC5730] Greeting.

5.3.  Extension Behavior

5.3.1.  SMTPUTF8 compliant addresses Extension Negotiated

   If both client and server have indicated the support of the SMTPUTF8
   addresses during the session establishment, they MUST be able to
   process the SMTPUTF8 address in any message having an email property
   during the established EPP session.  Below are the server and client
   obligations when the SMTPUTF8 extension has been successfuly
   negotiated in the EPP session.

   The server MUST satisfy the following obligations when the SMTPUTF8
   extension has been negotiated:

   *  Accept SMTPUTF8 compliant addresses for all email properties in
      the EPP session negotiated object extensions and command-response
      extensions.  For example the <contact:email> element in [RFC5733]
      and the <org:email> element in [RFC8543].

   *  Accept SMTPUTF8 compliant addresses for all registry zones (e.g.,
      top-level domains) authorized for the client in the EPP session.

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   *  Email address validation based on SMTPUTF8 validation rules
      defined in Section 3

   *  Storage of email properties that support internationalized
      characters.

   *  Return SMTPUTF8 compliant addresses for all email properties in
      the EPP responses.

   The client MUST satisfy the following obligations when the SMTPUTF8
   extension has been negotiated:

   *  Provide SMTPUTF8 compliant addresses for all e-mail properties in
      the EPP session negotiated object extensions and command-response
      extensions.  For example the <contact:email> element in [RFC5733]
      and the <org:email> element in [RFC8543].

   *  Provide SMTPUTF8 compliant addresses for all registry zones (e.g.,
      top-level domains) authorized for the client in the EPP session.

   *  Accept SMTPUTF8 compliant addresses in the EPP responses for all
      email properties in the EPP session negotiated object extensions
      and command-response extensions.

5.3.2.  SMTPUTF8 Extension Not Negotiated

   The lack of SMTPUTF8 adresses support can cause data and functional
   issues, so an SMTPUTF8 supporting client or server needs to handle
   cases where the opposite party doesn't support SMTPUTF8 addresses
   processing.  Below are the server and client obligations when the
   SMTPUTF8 extension is not negotiated due to the lack of support by
   the peer.

   The SMTPUTF8 supporting server MUST satisfy the following obligations
   when the client does not support the SMTPUTF8 extension:

   *  When the email property is required in the EPP command, the server
      MUST validate the email property sent by the client using the
      ASCII email validation rules.

   *  When the email property is optional in the EPP command, if the
      client supplies the email property the server MUST validate the
      email property using the ASCII email validation rules.

   *  When the email property is required in the EPP response, the
      server MUST validate whether the email property is an SMTPUTF8
      address and if so return the error code 2308 "Data management
      policy violation".

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   *  When the email property is optional in the EPP response and is
      provided, the server MUST validate whether the email property is
      an SMTPUTF8 address and if so return the error code 2308 "Data
      management policy violation".

   The SMTPUTF8 supporting client MUST satisfy the following obligations
   when the server does not support the SMTPUTF8 extension:

   *  When the email property is required in the EPP command and the
      email property is an SMTPUTF8 address, the client MUST provide an
      ASCII email address.  The provided email address should provide a
      way to contact the registrant.

   *  When the email property is optional in the EPP command and the
      email property is an SMTPUTF8 address and client does not have an
      ASCII address providing a way to contact the registrant, the
      client MUST omit the email property.  If the email property is
      provided, the client MUST provide an ASCII email address.

6.  EPP Command Mapping

   A detailed description of the EPP syntax and semantics can be found
   in the EPP core protocol specification [RFC5730].  This section
   defines the provisioning of an alternate email address.

6.1.  EPP Query Commands

   EPP provides three commands to retrieve object information: <check>
   to determine if an object can be provisioned, <info> to retrieve
   information associated with an object, and <transfer> to retrieve
   object-transfer status information.

6.1.1.  EPP <check> Command

   This extension does not add any elements to the EPP <check> command
   or <check> response described in [RFC5730].

6.1.2.  EPP <info> Command

   This extension does not add any elements to the EPP <info> command
   response described in [RFC5730].

   If the query was successful, the server replies with an <eai:eai>
   element (Section 4) along with the regular EPP <resData>.

   The following is an example <info> contact response using the
   <eai:eai> extension with no alternate email:

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   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:    </result>
   S:    <resData>
   S:      <contact:infData
   S:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   S:        <contact:id>sh8013</contact:id>
   S:        <contact:roid>SH8013-REP</contact:roid>
   S:        <contact:status s="linked"/>
   S:        <contact:status s="clientDeleteProhibited"/>
   S:        <contact:postalInfo type="int">
   S:          <contact:name>John Doe</contact:name>
   S:          <contact:org>Example Inc.</contact:org>
   S:          <contact:addr>
   S:            <contact:street>123 Example Dr.</contact:street>
   S:            <contact:street>Suite 100</contact:street>
   S:            <contact:city>Dulles</contact:city>
   S:            <contact:sp>VA</contact:sp>
   S:            <contact:pc>20166-6503</contact:pc>
   S:            <contact:cc>US</contact:cc>
   S:          </contact:addr>
   S:        </contact:postalInfo>
   S:        <contact:voice x="1234">+1.7035555555</contact:voice>
   S:        <contact:fax>+1.7035555556</contact:fax>
   S:        <contact:email>麥克風@example.com</contact:email>
   S:        <contact:clID>ClientY</contact:clID>
   S:        <contact:crID>ClientX</contact:crID>
   S:        <contact:crDate>1999-04-03T22:00:00.0Z</contact:crDate>
   S:        <contact:upID>ClientX</contact:upID>
   S:        <contact:upDate>1999-12-03T09:00:00.0Z</contact:upDate>
   S:        <contact:trDate>2000-04-08T09:00:00.0Z</contact:trDate>
   S:        <contact:authInfo>
   S:          <contact:pw>2fooBAR</contact:pw>
   S:        </contact:authInfo>
   S:        <contact:disclose flag="0">
   S:          <contact:voice/>
   S:          <contact:email/>
   S:        </contact:disclose>
   S:      </contact:infData>
   S:    </resData>
   S:    <extension>
   S:      <eai:eai
   S:       xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   S:        <eai:email/>
   S:      </eai:eai>

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   S:    </extension>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

       Figure 1: Example <info> contact response using the <eai:eai>
                     extension with no alternate email

   The following is an example <info> contact response using the
   <eai:eai> extension with an ASCII alternate email:

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:    </result>
   S:    <resData>
   S:      <contact:infData
   S:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   S:        <contact:id>sh8013</contact:id>
   S:        <contact:roid>SH8013-REP</contact:roid>
   S:        <contact:status s="linked"/>
   S:        <contact:status s="clientDeleteProhibited"/>
   S:        <contact:postalInfo type="int">
   S:          <contact:name>John Doe</contact:name>
   S:          <contact:org>Example Inc.</contact:org>
   S:          <contact:addr>
   S:            <contact:street>123 Example Dr.</contact:street>
   S:            <contact:street>Suite 100</contact:street>
   S:            <contact:city>Dulles</contact:city>
   S:            <contact:sp>VA</contact:sp>
   S:            <contact:pc>20166-6503</contact:pc>
   S:            <contact:cc>US</contact:cc>
   S:          </contact:addr>
   S:        </contact:postalInfo>
   S:        <contact:voice x="1234">+1.7035555555</contact:voice>
   S:        <contact:fax>+1.7035555556</contact:fax>
   S:        <contact:email>麥克風@example.com</contact:email>
   S:        <contact:clID>ClientY</contact:clID>
   S:        <contact:crID>ClientX</contact:crID>
   S:        <contact:crDate>1999-04-03T22:00:00.0Z</contact:crDate>
   S:        <contact:upID>ClientX</contact:upID>
   S:        <contact:upDate>1999-12-03T09:00:00.0Z</contact:upDate>
   S:        <contact:trDate>2000-04-08T09:00:00.0Z</contact:trDate>

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   S:        <contact:authInfo>
   S:          <contact:pw>2fooBAR</contact:pw>
   S:        </contact:authInfo>
   S:        <contact:disclose flag="0">
   S:          <contact:voice/>
   S:          <contact:email/>
   S:        </contact:disclose>
   S:      </contact:infData>
   S:    </resData>
   S:    <extension>
   S:      <eai:eai
   S:       xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   S:        <eai:email>jdoe@example.com</eai:email>
   S:      </eai:eai>
   S:    </extension>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

       Figure 2: Example <info> contact response using the <eai:eai>
                  extension with an ASCII alternate email

   The following is an example <info> contact response using the
   <eai:eai> extension with an SMTPUTF8 alternate email:

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:    </result>
   S:    <resData>
   S:      <contact:infData
   S:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   S:        <contact:id>sh8013</contact:id>
   S:        <contact:roid>SH8013-REP</contact:roid>
   S:        <contact:status s="linked"/>
   S:        <contact:status s="clientDeleteProhibited"/>
   S:        <contact:postalInfo type="int">
   S:          <contact:name>John Doe</contact:name>
   S:          <contact:org>Example Inc.</contact:org>
   S:          <contact:addr>
   S:            <contact:street>123 Example Dr.</contact:street>
   S:            <contact:street>Suite 100</contact:street>
   S:            <contact:city>Dulles</contact:city>

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   S:            <contact:sp>VA</contact:sp>
   S:            <contact:pc>20166-6503</contact:pc>
   S:            <contact:cc>US</contact:cc>
   S:          </contact:addr>
   S:        </contact:postalInfo>
   S:        <contact:voice x="1234">+1.7035555555</contact:voice>
   S:        <contact:fax>+1.7035555556</contact:fax>
   S:        <contact:email>jdoe@example.com</contact:email>
   S:        <contact:clID>ClientY</contact:clID>
   S:        <contact:crID>ClientX</contact:crID>
   S:        <contact:crDate>1999-04-03T22:00:00.0Z</contact:crDate>
   S:        <contact:upID>ClientX</contact:upID>
   S:        <contact:upDate>1999-12-03T09:00:00.0Z</contact:upDate>
   S:        <contact:trDate>2000-04-08T09:00:00.0Z</contact:trDate>
   S:        <contact:authInfo>
   S:          <contact:pw>2fooBAR</contact:pw>
   S:        </contact:authInfo>
   S:        <contact:disclose flag="0">
   S:          <contact:voice/>
   S:          <contact:email/>
   S:        </contact:disclose>
   S:      </contact:infData>
   S:    </resData>
   S:    <extension>
   S:      <eai:eai
   S:       xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   S:        <eai:email>麥克風@example.com</eai:email>
   S:      </eai:eai>
   S:    </extension>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

       Figure 3: Example <info> contact response using the <eai:eai>
                 extension with an SMTPUTF8 alternate email

6.1.3.  EPP <transfer> Query Command

   This extension does not add any elements to the EPP <transfer> query
   command or <transfer> query response described in [RFC5730].

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6.2.  EPP Transform Commands

   EPP provides five commands to transform objects: <create> to create
   an instance of an object, <delete> to delete an instance of an
   object, <renew> to extend the validity period of an object,
   <transfer> to manage object sponsorship changes, and <update> to
   change information associated with an object.

6.2.1.  EPP <create> Command

   This extension defines additional elements to extend the EPP <create>
   command of an object mapping like [RFC5733].

   The EPP <create> command provides a transform operation that allows a
   client to create an instance of an object.  In addition to the EPP
   command elements described in an object mapping like [RFC5733], the
   command MUST contain a child <eai:eai> element (Section 4) for the
   client to be set an alternate email.  If the alternate email does not
   apply to the object, the server MUST return an EPP error result code
   of 2201.

   The following is an example <create> command to create a contact
   object with an alternate ASCII email:

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   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C:  <command>
   C:    <create>
   C:      <contact:create
   C:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:        <contact:id>sh8013</contact:id>
   C:        <contact:postalInfo type="int">
   C:          <contact:name>John Doe</contact:name>
   C:          <contact:org>Example Inc.</contact:org>
   C:          <contact:addr>
   C:            <contact:street>123 Example Dr.</contact:street>
   C:            <contact:street>Suite 100</contact:street>
   C:            <contact:city>Dulles</contact:city>
   C:            <contact:sp>VA</contact:sp>
   C:            <contact:pc>20166-6503</contact:pc>
   C:            <contact:cc>US</contact:cc>
   C:          </contact:addr>
   C:        </contact:postalInfo>
   C:        <contact:voice x="1234">+1.7035555555</contact:voice>
   C:        <contact:fax>+1.7035555556</contact:fax>
   C:        <contact:email>麥克風@example.com</contact:email>
   C:        <contact:authInfo>
   C:          <contact:pw>2fooBAR</contact:pw>
   C:        </contact:authInfo>
   C:        <contact:disclose flag="0">
   C:          <contact:voice/>
   C:          <contact:email/>
   C:        </contact:disclose>
   C:      </contact:create>
   C:    </create>
   C:    <extension>
   C:      <eai:eai
   C:       xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   C:        <eai:email>jdoe@example.com</eai:email>
   C:      </eai:eai>
   C:    </extension>
   C:    <clTRID>ABC-12345</clTRID>
   C:  </command>
   C:</epp>

       Figure 4: Example <create> command to create a contact object
                       with an alternate ASCII email

   The following is an example <create> command to create a contact
   object with an alternate SMTPUTF8 email:

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   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C:  <command>
   C:    <create>
   C:      <contact:create
   C:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:        <contact:id>sh8013</contact:id>
   C:        <contact:postalInfo type="int">
   C:          <contact:name>John Doe</contact:name>
   C:          <contact:org>Example Inc.</contact:org>
   C:          <contact:addr>
   C:            <contact:street>123 Example Dr.</contact:street>
   C:            <contact:street>Suite 100</contact:street>
   C:            <contact:city>Dulles</contact:city>
   C:            <contact:sp>VA</contact:sp>
   C:            <contact:pc>20166-6503</contact:pc>
   C:            <contact:cc>US</contact:cc>
   C:          </contact:addr>
   C:        </contact:postalInfo>
   C:        <contact:voice x="1234">+1.7035555555</contact:voice>
   C:        <contact:fax>+1.7035555556</contact:fax>
   C:        <contact:email>jdoe@example.com</contact:email>
   C:        <contact:authInfo>
   C:          <contact:pw>2fooBAR</contact:pw>
   C:        </contact:authInfo>
   C:        <contact:disclose flag="0">
   C:          <contact:voice/>
   C:          <contact:email/>
   C:        </contact:disclose>
   C:      </contact:create>
   C:    </create>
   C:    <extension>
   C:      <eai:eai
   C:       xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   C:        <eai:email>麥克風@example.com</eai:email>
   C:      </eai:eai>
   C:    </extension>
   C:    <clTRID>ABC-12345</clTRID>
   C:  </command>
   C:</epp>

       Figure 5: Example <create> command to create a contact object
                      with an alternate SMTPUTF8 email

   This extension does not add any elements to the EPP <create> response
   described in [RFC5730].

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6.2.2.  EPP <delete> Command

   This extension does not add any elements to the EPP <delete> command
   or <delete> response described in [RFC5730].

6.2.3.  EPP <renew> Command

   This extension does not add any elements to the EPP <renew> command
   or <renew> response described in [RFC5730].

6.2.4.  EPP <transfer> Command

   This extension does not add any elements to the EPP <transfer>
   command or <transfer> response described in [RFC5730].

6.2.5.  EPP <update> Command

   This extension defines additional elements to extend the EPP <update>
   command of an object mapping like [RFC5733].

   The EPP <update> command provides a transform operation that allows a
   client to update an instance of an object.  In addition to the EPP
   command elements described in an object mapping like [RFC5733], the
   command MUST contain a child <eai:eai> element (Section 4) for the
   client to be set or unset an alternate email.  If the alternate email
   does not apply to the object, the server MUST return an EPP error
   result code of 2201.

   The following is an example <update> command to set a contact object
   with an alternate ASCII email:

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   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C: <command>
   C:   <update>
   C:     <contact:update
   C:      xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:       <contact:id>sh8013</contact:id>
   C:     </contact:update>
   C:   </update>
   C:   <extension>
   C:     <eai:eai
   C:      xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   C:       <eai:email>jdoe@example.com</eai:email>
   C:     </eai:eai>
   C:   </extension>
   C:   <clTRID>ABC-12345</clTRID>
   C: </command>
   C:</epp>

      Figure 6: Example <update> command to set a contact object with
                          an alternate ASCII email

   The following is an example <update> command to set a contact object
   with an alternate SMTPUTF8 email:

   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C: <command>
   C:   <update>
   C:     <contact:update
   C:      xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:       <contact:id>sh8013</contact:id>
   C:     </contact:update>
   C:   </update>
   C:   <extension>
   C:     <eai:eai
   C:      xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   C:       <eai:email>麥克風@example.com</eai:email>
   C:     </eai:eai>
   C:   </extension>
   C:   <clTRID>ABC-12345</clTRID>
   C: </command>
   C:</epp>

      Figure 7: Example <update> command to set a contact object with
                        an alternate SMTPUTF8 email

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   The following is an example <update> command to unset a contact
   object alternate email:

   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C: <command>
   C:   <update>
   C:     <contact:update
   C:      xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:       <contact:id>sh8013</contact:id>
   C:     </contact:update>
   C:   </update>
   C:   <extension>
   C:     <eai:eai
   C:      xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0">
   C:       <eai:email/>
   C:     </eai:eai>
   C:   </extension>
   C:   <clTRID>ABC-12345</clTRID>
   C: </command>
   C:</epp>

        Figure 8: Example <update> command to unset a contact object
                              alternate email

   This extension does not add any elements to the EPP <create> response
   described in [RFC5730].

7.  Formal Syntax

   The EPP SMTPUTF8 Addresses Extension schema is presented here.

   The formal syntax shown here is a complete XML Schema representation
   of the object mapping suitable for automated validation of EPP XML
   instances.  The <CODE BEGINS> and <CODE ENDS> tags are not part of
   the XML Schema; they are used to note the beginning and ending of the
   XML Schema for URI registration purposes.

7.1.  SMTPUTF8 Addresses Schema

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   <CODE BEGINS>
   <?xml version="1.0" encoding="UTF-8"?>
   <schema xmlns="http://www.w3.org/2001/XMLSchema"
     xmlns:eai="urn:ietf:params:xml:ns:epp:eai-1.0"
     targetNamespace="urn:ietf:params:xml:ns:epp:eai-1.0"
     elementFormDefault="qualified">
     <annotation>
       <documentation>Extensible Provisioning Protocol v1.0
          SMTPUTF8 Addresses Schema.</documentation>
     </annotation>
     <!-- Create, Update, and Info Response extension element -->
     <element name="eai" type="eai:eaiType" />
     <!--
       Single email element that can be empty
      -->
     <complexType name="eaiType">
       <sequence>
         <element name="email"
           type="token"/>
       </sequence>
     </complexType>
     <!--
    End of schema.
    -->
   </schema>
   <CODE ENDS>

8.  IANA Considerations

8.1.  XML Namespace

   This document uses URNs to describe XML namespaces conforming to a
   registry mechanism described in RFC 3688 [RFC3688].  The following
   URI assignment should be made by IANA:

   Registration request for the eai namespace:

   URI:  urn:ietf:params:xml:ns:epp:eai-1.0
   Registrant Contact:  IESG
   XML:  None.  Namespace URIs do not represent an XML specification.

   Registration request for the eai XML Schema:

   URI:  urn:ietf:params:xml:schema:epp:eai-1.0
   Registrant Contact:  IESG
   XML:  See the "Formal Syntax" section of this document.

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8.2.  EPP Extension Registry

   The EPP extension described in this document should be registered by
   IANA in the "Extensions for the Extensible Provisioning Protocol
   (EPP)" registry described in RFC 7451 [RFC7451].  The details of the
   registration are as follows:

   Name of Extension:  "Use of Internationalized Email Addresses in EPP
      protocol"
   Document status:  Standards Track
   Reference:  RFC 8807
   Registrant Name and Email Address:  IESG, <iesg@ietf.org>
   Top-Level Domains(TLDs):  Any
   IPR Disclosure:  None
   Status:  Active
   Notes:  None

9.  Implementation Status

   Note to RFC Editor: Please remove this section and the reference to
   RFC 7942 [RFC7942] before publication.

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in RFC 7942
   [RFC7942].  The description of implementations in this section is
   intended to assist the IETF in its decision processes in progressing
   drafts to RFCs.  Please note that the listing of any individual
   implementation here does not imply endorsement by the IETF.
   Furthermore, no effort has been spent to verify the information
   presented here that was supplied by IETF contributors.  This is not
   intended as, and must not be construed to be, a catalog of available
   implementations or their features.  Readers are advised to note that
   other implementations may exist.

   According to RFC 7942 [RFC7942], "this will allow reviewers and
   working groups to assign due consideration to documents that have the
   benefit of running code, which may serve as evidence of valuable
   experimentation and feedback that have made the implemented protocols
   more mature.  It is up to the individual working groups to use this
   information as they see fit".

9.1.  Verisign EPP SDK

   Organization: Verisign Inc.

   Name: Verisign EPP SDK

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   Description: The Verisign EPP SDK includes both a full client
   implementation and a full server stub implementation of draft-ietf-
   regext-epp-eai.

   Level of maturity: Development

   Coverage: All aspects of the protocol are implemented.

   Licensing: GNU Lesser General Public License

   Contact: jgould@verisign.com

   URL: https://www.verisign.com/en_US/channel-resources/domain-
   registry-products/epp-sdks

10.  Security Considerations

   As is noted in Section 10.1 and Section 13 of [RFC6530],
   unconstrained Unicode in email addresses can introduce a class of
   security threats that do not exist with all-ASCII email addresses.
   As EPP exists in ecosystems where email addresses passed in EPP are
   displayed in RDAP and other services and copy-and-paste of these
   email addresses is common for businesses transferring domains via
   EPP, there should be safeguards against these threats.  Therefore,
   usage of the SMTPUTF8 email addresses as specified in this document
   SHOULD be done with policies that disallow the use of unconstrained
   Unicode.  The domain-part of these SMTPUTF8 email addresses SHOULD
   conform to IDNA2008.  The local-part of these SMTPUTF8 email
   addresses SHOULD be restricted to Unicode that does not introduce the
   threats noted in [RFC6530].  One such possible solution would be to
   disallow characters outside of Unicode Annex 31
   (https://unicode.org/reports/tr31/).

   As email address is often a primary end user contact, an invalid
   email address may put the communication with the end user into risk
   in case when such contact is necessary.  In case of an invalid domain
   name in the email address a malicious actor can register a valid
   domain name with similar U-label (homograph attack) and get a control
   over the domain name associated with the contact using social
   engineering techniques.  To reduce the risk of the use of invalid
   domain names in email addresses, registries SHOULD validate the
   domain name syntax in the provided email addresses and validate
   whether the domain name consists of the code points allowed by IDNA
   Rules and Derived Property Values (https://www.iana.org/assignments/
   idna-tables).

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   When the SMTPUTF8 extension is negotiated by both the client and the
   server, the client and server obligations defined in Section 5.3.1
   MUST be satisfied.  If the obligations are not satisfied by either
   the client or server, the SMTPUTF8 address may be mishandled in
   processing or storage and be unusable.

11.  Acknowledgments

   The authors would like to thank Alexander Mayrhofer, Chris Lonvick,
   Gustavo Lozano, Jody Kolker, John C Klensin, John Levine, Klaus
   Malorny, Marc Blanchet, Marco Schrieck, Mario Loffredo, Murray S.
   Kucherawy, Patrick Mevzek, Pete Resnick, Scott Hollenbeck, Takahiro
   Nemoto, Taras Heichenko, and Thomas Corte for their careful review
   and valuable comments.

12.  References

12.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.27487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.27487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC5321]  Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
              DOI 10.17487/RFC5321, October 2008,
              <https://www.rfc-editor.org/info/rfc5321>.

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,
              <https://www.rfc-editor.org/info/rfc5322>.

   [RFC5730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
              STD 69, RFC 5730, DOI 10.27487/RFC5730, August 2009,
              <https://www.rfc-editor.org/info/rfc5730>.

   [RFC5733]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
              Contact Mapping", STD 69, RFC 5733, DOI 10.27487/RFC5733,
              August 2009, <https://www.rfc-editor.org/info/rfc5733>.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, DOI 10.17487/RFC5890, August 2010,
              <https://www.rfc-editor.org/info/rfc5890>.

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   [RFC6530]  Klensin, J. and Y. Ko, "Overview and Framework for
              Internationalized Email", RFC 6530, DOI 10.17487/RFC6530,
              February 2012, <https://www.rfc-editor.org/info/rfc6530>.

   [RFC6531]  Yao, J. and W. Mao, "SMTP Extension for Internationalized
              Email", RFC 6531, DOI 10.17487/RFC6531, February 2012,
              <https://www.rfc-editor.org/info/rfc6531>.

   [RFC6532]  Yang, A., Steele, S., and N. Freed, "Internationalized
              Email Headers", RFC 6532, DOI 10.17487/RFC6532, February
              2012, <https://www.rfc-editor.org/info/rfc6532>.

   [RFC7942]  Sheffer, Y. and A. Farrel, "Improving Awareness of Running
              Code: The Implementation Status Section", BCP 205,
              RFC 7942, DOI 10.17487/RFC7942, July 2016,
              <https://www.rfc-editor.org/info/rfc7942>.

   [RFC8590]  Gould, J. and K. Feher, "Change Poll Extension for the
              Extensible Provisioning Protocol (EPP)", RFC 8590,
              DOI 10.17487/RFC8590, May 2019,
              <https://www.rfc-editor.org/info/rfc8590>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.27487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

12.2.  Informative References

   [RFC7451]  Hollenbeck, S., "Extension Registry for the Extensible
              Provisioning Protocol", RFC 7451, DOI 10.27487/RFC7451,
              February 2015, <https://www.rfc-editor.org/info/rfc7451>.

   [RFC8543]  Zhou, L., Kong, N., Yao, J., Gould, J., and G. Zhou,
              "Extensible Provisioning Protocol (EPP) Organization
              Mapping", RFC 8543, DOI 10.27487/RFC8543, March 2019,
              <https://www.rfc-editor.org/info/rfc8543>.

Appendix A.  Change History

A.1.  Change from 00 to 01

   1.  Changed from update of RFC 5733 to use the "Placeholder Text and
       a New Email Element" EPP Extension approach.

A.2.  Change from 01 to 02

   1.  Fixed the XML schema and the XML examples based on validating
       them.

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   2.  Added James Gould as co-author.

   3.  Updated the language to apply to any EPP object mapping and to
       use the EPP contact mapping as an example.

   4.  Updated the structure of document to be consistent with the other
       Command-Response Extensions.

   5.  Replaced the use of "eppEAI" in the XML namespace and the XML
       namespace prefix with "eai".

   6.  Changed to use a pointed XML namespace with "0.2" instead of
       "1.0".

A.3.  Change from 02 to 03

   1.  The approach has changed to use the concept of Functional EPP
       Extension.

   2.  The examples are removed

A.4.  Change from 03 to 04

   1.  More detailed reference to email syntax is provided

   2.  The shortened eai namespace reference is removed

A.5.  Change from 04 to the regext 01 version

   1.  Provided the recommended placeholder value

A.6.  Change from the regext 01 to regext 02 version

   1.  Removed the concept of the placeholder value

A.7.  Change from the regext 02 to regext 03 version

   1.  Changed to use a pointed XML namespace with "0.3" instead of
       "0.2".

   2.  Some wording improvements

A.8.  Change from the regext 03 to regext 04 version

   1.  Some nitpicking

A.9.  Change from the regext 04 to regext 05 version

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   1.  Some nitpicking

   2.  The "Implementation considerations" section is removed

A.10.  Change from the regext 05 to regext 06 version

   1.  Some nitpicking

A.11.  Change from the regext 06 to regext 07 version

   1.  Namespace version set to 1.0

A.12.  Change from the regext 07 to regext 08 version

   1.  Information about implementations is provided.

   2.  Acknowledgments section is added.

   3.  Reference to RFC 7451 is moved to Informative.

   4.  IPR information is provided

   5.  Sections are reordered to align with the other regext documents

A.13.  Change from the regext 08 to regext 09 version

   1.  Nitpicking according to Murray S.  Kucherawy review

A.14.  Change from the regext 09 to regext 10 version

   1.  Some nitpicking in the security considerations.

A.15.  Change from the regext 10 to regext 11 version

   1.  Nitpicking according mostly GenArt review.

A.16.  Change from the regext 11 to regext 12 version

   1.  XML schema registration request removed.

A.17.  Change from the regext 12 to regext 13 version

   1.  Document updated according to SecDir and ART-ART review.

A.18.  Change from the regext 13 to regext 14 version

   1.  Document updated according the IANA review #1231866.

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A.19.  Change from the regext 14 to regext 15 version

   1.  Document updated according to ART-ART review.

A.20.  Change from the regext 15 to regext 16 version

   1.  Document removed the definition of the concept of a functional
       extension and updated to use a command-response extension, based
       on the feedback from John C Klensin.

   2.  Document removed the EAI abbreviation and uses SMTPUTF8 as
       umbrella term instead, based on the feedback from John C Klensin.

A.21.  Change from the regext 16 to regext 17 version

   1.  Added support for an alternate email during a transition period,
       based on feedback from John C Klensin.

A.22.  Change from the regext 17 to regext 18 version

   1.  Roll back to approach in -16 with the Cardinality of One Option,
       posted to and supported on the mailing list.

   2.  Replaced references of eai to smtputf8, based on feedback from
       John C Klensin.

   3.  Revised the Security Considerations section based on feedback and
       text from Andy Newton.

A.23.  Change from the regext 18 to regext 19 version

   1.  Reverted back to -17 with support for one or two email addresses
       using either ASCII or SMTPUTF8 and remove any reference to the
       requirement for an ASCII email address and remove the concept of
       a transition period.

A.24.  Change from the regext 19 to regext 20 version

   1.  Reverted Security Considerations section back to the content in
       -18 based on feedback from Andy Newton.

Authors' Addresses

   Dmitry Belyavskiy
   8 marta st.
   Moscow
   127083
   Russian Federation

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   Phone: +7 916 262 5593
   Email: beldmit@gmail.com

   James Gould
   VeriSign, Inc.
   12061 Bluemont Way
   Reston, VA 20190
   United States of America
   Email: jgould@verisign.com
   URI:   http://www.verisigninc.com

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