XEP-xxxx: Occupant Mute Synchronization

Abstract: Allows synchronizing a list of muted group chat participants between multiple clients.
Author: Matthew Wild
Copyright: © 2026 – 2026 XMPP Standards Foundation. SEE LEGAL NOTICES.
Status: ProtoXEP
WARNING: This document has not yet been accepted for consideration or approved in any official manner by the XMPP Standards Foundation, and this document is not yet an XMPP Extension Protocol (XEP). If this document is accepted as a XEP by the XMPP Council, it will be published at <https://xmpp.org/extensions/> and announced on the <standards@xmpp.org> mailing list.
Type: Standards Track
Version: 0.0.1 (2026-03-31)

Document Lifecycle

Experimental
Proposed
Stable
Final

1. Introduction¶

For blocking remote users, XMPP already supports Blocking Command (XEP-0191) [1] which uses a shared account-wide blocklist. However, in the context of group chats this is inadequate - it would allow blocking the entire group chat (which is sometimes useful) but does not allow reliably blocking individual participants within a chat.

This specification describes a mechanism through which a user can block (also called 'muting' or 'ignoring') a group chat participant and have this synchronized across all their clients.

2. Requirements¶

3. Use Cases¶

3.1 Client adds new muted participant¶

To add a new mute, the client updates the XEP-0402 bookmark for the group chat to include a <muted/> element qualified by the 'urn:xmpp:muted:0' namespace in the <extensions/> element of the bookmark.

The <muted/> element contains zero or more <mute/> elements. Each <mute/> element MUST have an 'id' attribute set to the XEP-0421 occupant identifier of an occupant that is to be muted.

Example 1. Client adds a participant mute to the bookmark¶

<iq from='juliet@capulet.lit/balcony' type='set' id='mute2'>
  <pubsub xmlns='http://jabber.org/protocol/pubsub'>
    <publish node='urn:xmpp:bookmarks:1'>
      <item id='orchard@conference.shakespeare.lit'>
        <conference xmlns='urn:xmpp:bookmarks:1'
                    name='The Orchard'
                    autojoin='true'>
          <extensions>
            <muted xmlns='urn:xmpp:mute:0'>
                <mute occupant='dd72603deec90a38ba552f7c68cbcc61bca202cd'/>
            </muted>
          </extensions>
        </conference>
      </item>
    </publish>
    <publish-options>
      <x xmlns='jabber:x:data' type='submit'>
        <field var='FORM_TYPE' type='hidden'>
          <value>http://jabber.org/protocol/pubsub#publish-options</value>
        </field>
        <field var='pubsub#persist_items'>
          <value>true</value>
        </field>
        <field var='pubsub#max_items'>
          <value>max</value>
        </field>
        <field var='pubsub#send_last_published_item'>
          <value>never</value>
        </field>
        <field var='pubsub#access_model'>
          <value>whitelist</value>
        </field>
      </x>
    </publish-options>
  </pubsub>
</iq>

4. Business Rules¶

Clients SHOULD maintain a local list of muted participants in each group chat and keep it synchronized with the bookmarks (publishing local changes, and reacting to changes received from other clients).

If the <muted/> element becomes empty, it SHOULD be removed from the bookmark. Clients receiving bookmarks with an empty or absent <muted/> element MUST assume there are no muted participants within that chat.

5. Accessibility Considerations¶

There are no significant accessibility considerations for this protocol. This XEP does not mandate any particular UI for how messages from muted participants are handled. However, some guidance is provided to aid consistency between implementations and reduce the potential for confusion.

In general, clients SHOULD display an indication that a message was received (but not displayed) from a muted participant, to reduce confusion when conversations between other users and the muted participant occur.

Clients MAY also provide a way for a user to temporarily reveal the contents of a muted message, to provide necessary context.

Clients SHOULD retroactively hide messages from muted participants, and similarly unhide them when a participant is unmuted.

6. Internationalization Considerations¶

7. Security Considerations¶

8. Privacy Considerations¶

9. IANA Considerations¶

10. XMPP Registrar Considerations¶

11. Design Considerations¶

Alternative approaches were considered but rejected. Some users have tried using XEP-0191 to block occupant JIDs, and implementations have been tweaked to ensure this works as well as it can. However, this approach has several problems:

Server-side muting (in the group chat server or the user’s own server) was considered, but has similar issues relating to history availability, reliable sync, and so on.

The final approach that was considered was a separate PEP node for mutes. However, mutes are scoped to a group chat already by the way that occupant IDs are. This means it makes sense to store a per-chat list of mutes. We already have per-chat information storage in XEP-0402, so it made a lot of sense to move this information into the bookmark to avoid the two stores getting out of sync.

A downside of the approach used in this specification is that you can’t sync mutes for a chat without having a bookmark for it. This generally seems to be a non-issue, as practically all modern clients already automatically create bookmarks for chats they join as a matter of course, to ensure consistency across restarts and across clients.

Appendices

Appendix A: Document Information¶

Appendix B: Author Information¶

Matthew Wild

Appendix C: Legal Notices¶

Copyright

Permissions

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. ##

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 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.

IPR Conformance

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).

Visual Presentation

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Appendix D: Relation to XMPP¶

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) 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 <https://xmpp.org/community/> for a complete list.

Appendix F: Requirements Conformance¶

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.