Displayed Markers This specification introduces a method to let the sender, or multiple participants in a group chat, know that a client has displayed messages up to a certain point. This XMPP Extension Protocol is copyright © 1999 – 2024 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. ## 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 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 from, out of, or in connection with the Specification or the implementation, deployment, or other use of 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. This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA). 0333 Draft 2024-04-08 2017-03-01 2017-02-22 2017-02-11 Standards Track Standards Council XMPP Core XEP-0001 NOT_YET_ASSIGNED Spencer MacDonald im@spencermacdonald.com im@spencermacdonald.com Daniel Gultsch daniel@gultsch.de daniel@gultsch.de 1.0.0 2024-04-17 XEP Editor (dg) Accept as Stable as per Council Vote from 2024-04-17. 0.7.0 2024-04-04 dg
  • Change title to "Displayed Markers"
  • Bring back Service Discovery feature
 0.6.0 2024-03-21 dg
  • Add Business Rule about opportunistic Displayed Markers in 1:1 chats
 0.5.0 2024-03-06 dg
  • Remove <received/> to not replicate Message Delivery Receipts (XEP-0184) XEP-0184: Message Delivery Receipts <https://xmpp.org/extensions/xep-0184.html>. functionality.
  • Remove <acknowledged/> because it was not implemented in the last 10 years and apparently is not needed.
  • Remove Disco feature. Opting in via <markable/> is enough
 0.4.1 2023-07-19 gdk Changed discovery example to use client JIDs. 0.4 2020-04-15 mw Add notes about usage within MUCs. 0.3 2017-09-11 XEP Editor (jwi) Defer due to lack of activity. 0.2.1 2015-10-28 XEP Editor (mam)

Fixing typo ("cannot" repeated twice) (JC Brand).

 0.2 2013-09-05 sdm

Moved Thread outside of the Chat Marker.

 0.1 2013-07-11 psa

Initial published version approved by the XMPP Council.

 0.0.4 2013-07-06 sdm

Noted that Chat Markers is a heuristic solution.

Added markable element.

 0.0.3 2013-06-20 sdm

Changed read Chat Marker to displayed.

Removed stamp from Chat Marker.

Added thread to Chat Marker.

Changed namespace to allow for versioning.

 0.0.2 2013-06-11 sdm

Change to a message based protocol.

 0.0.1 2013-05-24 sdm

First draft.

Letting the sender and/or multiple participants of a group chat know that an entity has displayed (Colloquially known as read) a message is a common feature in modern instant messaging.

Message Delivery Receipts (XEP-0184) XEP-0184: Message Delivery Receipts <https://xmpp.org/extensions/xep-0184.html>. currently provides delivery receipts on a per message basis, but it does not provide any mechanism for the user to indicate that they have read the message.

This specification defines a protocol for the sender of a message to let the recipient know they are interested in whether the recipient’s client has displayed the message and a protocol for the recipient to respond to said request. In group chats the explicit request is omitted and participants opportunistically share their displayed state with others.

Displayed Markers carry a semantic of all messages up to this point.

Note: Displayed Markers do not mark each individual message, nor do they assume a reliable transport. This means that Displayed Markers can only provide a heuristic solution, but this is often satisfactory for the majority of use cases.

If an entity supports the Displayed Markers protocol, it MUST report that by including a Service Discovery (XEP-0030) XEP-0030: Service Discovery <https://xmpp.org/extensions/xep-0030.html>. feature of "urn:xmpp:chat-markers:0" in response to disco#info requests:

]]> ... ... ]]>

Support can also be determined via Entity Capabilities (XEP-0115) XEP-0115: Entity Capabilities <https://xmpp.org/extensions/xep-0115.html>. or Entity Capabilities 2.0 (XEP-0390) XEP-0390: Entity Capabilities 2.0 <https://xmpp.org/extensions/xep-0390.html>..

An entity interested to know if the recipient has displayed a message attaches a <markable/> element qualified by the 'urn:xmpp:chat-markers:0' namespace to the message. The message MUST possess an 'id' attribute for traceability.

Hi. How are you? ]]>

To let the sender know a message has been displayed an entity sends a message with a <displayed/> element qualified by the 'urn:xmpp:chat-markers:0' namespace. The <displayed/> element MUST have an 'id' attribute that copies the value from the 'id' attribute of the message it refers to.

A Displayed Marker MAY be sent to the bare JID of the entity that requested it.

If multiple messages are displayed at once an entity SHOULD only send a <displayed/> marker for the most recent, received message.

To prevent looping, an entity MUST NOT send a Displayed Marker as a response to a Displayed Marker.

]]>

Displayed Markers can be used within group chats to indicate read status of each occupant.

Within the context of a MUC messages are relayed through the MUC's own JID. In a MUC that preserves the 'id' attribute chosen by the sender of the message this 'id' attribute cannot be considered unique, as it may be unintentionally or even maliciously reused by another MUC occupant.

Therefore, if a MUC announces support for Unique and Stable Stanza IDs (XEP-0359) XEP-0359: Unique and Stable Stanza IDs <https://xmpp.org/extensions/xep-0359.html>. then clients MUST always use the MUC-assigned id for Displayed Markers. The id will be contained in a <stanza-id/> element inserted into the stanza with a 'by' attribute matching the MUC's own JID.

As per XEP-0359 security considerations, if XEP-0359 support is not announced on the MUC room's JID then <stanza-id/> elements with a 'by' attribute that match the MUC's JID should be considered spoofed and MUST be ignored.

In group chats the Displayed Marker MAY be sent opportunistically, meaning without an explicit <markable/> request from the sender. While the sender might not be interested in or have support for Display Markers, other participants of the group chat could be interested in them.

Act IV, Scene I Thrice the brinded cat hath mew'd. ]]> Act IV, Scene I ]]>

Graphical representations of displayed markers for example in the form of checkmarks need to be made available for visually impaired users.

Letting others know that one has displayed (read) a message is not a desirable feature for everyone. Clients SHOULD provide ways to opt-out of this feature.

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

This specification defines the following XML namespace:

  • 'urn:xmpp:chat-markers:0'

Earlier drafts of this specification included <received/> and <acknowledged/> with the same up to this point semantic as the remaining <displayed/>. However in the review phase it was concluded that most implementers prefer the per-message precision of Message Delivery Receipts (XEP-0184) XEP-0184: Message Delivery Receipts <https://xmpp.org/extensions/xep-0184.html>. for received tracking. While <displayed/> has been widely implemented during a 10+ year review phase there was seemingly no demand for <acknowledged/>.

 The protocol documented by this schema is defined in XEP-0333: http://xmpp.org/extensions/xep-0333.html ]]>