XEP-0091: Delayed Delivery

Abstract:This specification provides historical documentation of the jabber:x:delay namespace, which has been deprecated in favor the urn:xmpp:delay namespace defined in XEP-0203.
Author:Peter Saint-Andre
Copyright:© 1999 - 2009 XMPP Standards Foundation. SEE LEGAL NOTICES.
Last Updated:2007-03-29

WARNING: This document has been deprecated by the XMPP Standards Foundation. Implementation of the protocol described herein is not recommended. Developers desiring similar functionality should implement the protocol that supersedes this one (if any).

Table of Contents

1. Introduction
2. Protocol Definition
3. Examples
4. A Note on Time Formats
5. Security Considerations
6. IANA Considerations
7. XMPP Registrar Considerations
8. XML Schema

    A: Document Information
    B: Author Information
    C: Legal Notices
    D: Relation to XMPP
    E: Discussion Venue
    F: Requirements Conformance
    G: Notes
    H: Revision History

1. Introduction

Note: This specification has been deprecated in favor of Delayed Delivery [1].

This document provides canonical documentation of the 'jabber:x:delay' namespace, which was long used by Jabber applications to mark message or presence stanzas as delivered with a delay. This document is of historical importance only, since it has been deprecated in favor of XEP-0203.

2. Protocol Definition

The 'jabber:x:delay' namespace is used to provide timestamp information about data stored for later delivery. The most common uses of this namespace are to stamp:

Information about the delivery delay is communicated by adding to the <message/> or <presence/> stanza one and only one <x/> child qualified by the 'jabber:x:delay' namespace. This information is added by the server or component that delivers the information. The following attributes are allowed on the <x/> element:

In addition, the <x/> element MAY contain XML character data that provides a natural-language description of the reason for the delay.

3. Examples

Example 1. Receiving a Message Sent While Offline

    O blessed, blessed night! I am afeard.
    Being in night, all this is but a dream,
    Too flattering-sweet to be substantial.
  <x xmlns='jabber:x:delay'
    Offline Storage

Example 2. Receiving the Last Presence Update of Another Entity

<presence from='juliet@capulet.com/balcony' to='romeo@montague.net'>
  <x xmlns='jabber:x:delay'

Example 3. Receiving Cached Messages from a Conference Room

    By the pricking of my thumbs,
    Something wicked this way comes.
    Open, locks,
    Whoever knocks!
  <x xmlns='jabber:x:delay'

4. A Note on Time Formats

XMPP Date and Time Profiles [2] defines the lexical representation of dates, times, and datetimes in Jabber protocols. Unfortunately, the 'jabber:x:delay' namespace predates that definition, and uses a datetime format ("CCYYMMDDThh:mm:ss") that is inconsistent with XEP-0082 and XML Schema Part 2 [3]. Because a large base of deployed software uses the old format, this document specifies that applications using 'jabber:x:delay' SHOULD use the old format, not the format defined in XEP-0082. The timezone is be understood as UTC.

5. Security Considerations

Data qualified by the 'jabber:x:delay' can expose information about the sender's presence on the network at some time in the past. However, this introduces no new vulnerabilities, since the same information would have been available in real time.

6. IANA Considerations

This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [4].

7. XMPP Registrar Considerations

The 'jabber:x:delay' namespace is included in the protocol namespaces registry maintained by the XMPP Registrar [5].

8. XML Schema

<?xml version='1.0' encoding='UTF-8'?>


      The protocol documented by this schema is defined in
      XEP-0091: http://www.xmpp.org/extensions/xep-0091.html

      NOTE: This protocol has been deprecated in favor of the 
            Delayed Delivery protocol specified in XEP-0203:

  <xs:element name='x'>
        <xs:extension base='xs:string'>
          <xs:attribute name='from' type='xs:string' use='optional'/>
          <xs:attribute name='stamp' type='xs:string' use='required'/>



Appendix A: Document Information

Series: XEP
Number: 0091
Publisher: XMPP Standards Foundation
Status: Deprecated
Type: Historical
Version: 1.3
Last Updated: 2007-03-29
Expires: 2009-06-30
Approving Body: XMPP Council
Dependencies: XMPP Core
Supersedes: None
Superseded By: XEP-0203
Short Name: x-delay
Schema: <http://www.xmpp.org/schemas/x-delay.xsd>
Source Control: HTML  RSS

Appendix B: Author Information

Peter Saint-Andre

JabberID: stpeter@jabber.org
URI: https://stpeter.im/

Appendix C: Legal Notices


This XMPP Extension Protocol is copyright © 1999 - 2009 by the XMPP Standards Foundation (XSF).


Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. In no event shall the XMPP Standards Foundation or the authors of this Specification be liable for any claim, damages, or other liability, whether in an action of contract, tort, or otherwise, arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising out of the use or inability to use the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which may be found at <http://xmpp.org/extensions/ipr-policy.shtml> or obtained by writing to XSF, P.O. Box 1641, Denver, CO 80201 USA).

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 3920) and XMPP IM (RFC 3921) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.

Appendix E: Discussion Venue

The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.

Discussion on other xmpp.org discussion lists might also be appropriate; see <http://xmpp.org/about/discuss.shtml> for a complete list.

Errata may be sent to <editor@xmpp.org>.

Appendix F: Requirements Conformance

The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".

Appendix G: Notes

1. XEP-0203: Delayed Delivery <http://xmpp.org/extensions/xep-0203.html>.

2. XEP-0082: XMPP Date and Time Profiles <http://xmpp.org/extensions/xep-0082.html>.

3. XML Schema Part 2: Datatypes <http://www.w3.org/TR/xmlschema-2/>.

4. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.

5. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <http://xmpp.org/registrar/>.

Appendix H: Revision History

Version 1.3 (2007-03-29)

Per a vote of the XMPP Council, deprecated in favor of XEP-0203.


Version 1.2 (2004-08-17)

Specified that the timezone is to be understood as UTC; specified security considerations; corrected several small textual errors.


Version 1.1 (2004-02-24)

Corrected several small textual errors.


Version 1.0 (2003-10-08)

Per a vote of the Jabber Council, changed status to Active.


Version 0.1 (2003-05-22)

Initial version.