- Standards

by Dave Cridland

Hi all, I'm trying to summarise a discussion in the council@ chatroom, and - like an LLM - I am not perfect so may misrepresent or misunderstand some views. Errors, therefore, I shall claim as my own; views however are not. First, some history. In the early days of XEP-0045, each occupant corresponded to precisely one full jid (ie, a client session). All stanzas sent to the occupant jid were, therefore, forwarded through directly to that full jid. This general model of "pure forwarding" has been maintained throughout XEP-0045's history, but it has been modified heavily. Quite early on - Kev thought 2001, MattJ thought 2003 - the need to have vCards in particular be different started changing rules, and when Prosody started doing MUC (and also M-Link) they started intercepting vCard to the MUC occupant jid and forwarding that to the user's bare jid. Prosody now does this with PEP as well. In addition, "nick sharing" - allowing multiple full jids of the same user behind a single occupant jid - makes forwarding most IQ stanzas complicated. All this causes existing problems with preserving privacy in semi-anonymous rooms. What we do in the future (under MUC2/GC3/IRC4 whatever) broadly falls into 3 options that were discussed. Option 1: The occupant jid forwards nothing, but has a way of requesting a contact jid. Option 2: The occupant jid forwards everything to the user's bare jid, and their server "deals" with it. Option 3: The occupant jid responds itself, without forwarding, and data (vCards, PEP, etc) need to be uploaded by the user and stored by the MUC. Option 4: The occupant jid has rules set by the user, which cause it to either forward or reject particular traffic. I imagine some of these rules will cause PEP subscriptions and event forwarding/fanout, potentially. There were proponents of each of these approaches (and some proponents of multiple). There's a further discussion in xsf@ that I've not yet properly read. My opinions follow: Of these options, I think I'd like Option 4, but will settle for Option 2. Option 2 feels like the natural fallback for Option 4 anyway. One outcome is that in Future-MUC, there's an implication that Private Messages, PEP, and vCard will go to the *bare* Jid, and that unless we do something "clever", so will Jingle calls to Occupants. We would then control these with existing (or new) access control on our own server, or Option 4's new rules, or some combination of both. I appreciate the simplicity of Option 1, but I think it's too simple - even for Private Messages I'd need to reveal my identity. If I'm in a sensitive room (say a healthcare related one) I might really want (or need) PMs but not be willing to reveal my identity. Option 3 seems very heavyweight and expensive to maintain and manage. I don't particularly want to upload an avatar (and more) to each MUC room, and nor do I see how those will work with (for example) Jingle. As noted, I may have misconstrued the options presented! Dave.

2 days, 16 hours

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Proposed XMPP Extension: New MUC

by Daniel Gultsch

The XMPP Extensions Editor has received a proposal for a new XEP. Title: New MUC Abstract: This document specifies an enhanced Multi-User Chat protocol that is broadly backwards compatible with that of XEP-0045, but adds a number of key improvements. URL: https://xmpp.org/extensions/inbox/new-muc.html The Council will decide in the next two weeks whether to accept this proposal as an official XEP.

2 days, 21 hours

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XMPP Council Agenda 2026-05-05

by Daniel Gultsch

Good Morning Council Members, the next XMPP Council Meeting will take place on, Tuesday, May 5 2026 at 15:30 UTC in xmpp:council@muc.xmpp.org?join The Agenda is as follows: 1) Roll call 2) Agenda Bashing 3) Editors update * Proposed XMPP Extension: Payment Required (https://xmpp.org/extensions/inbox/payment-required.html) * Proposed XMPP Extension: Emoji Markup (https://xmpp.org/extensions/inbox/emoji-markup.html) * Proposed XMPP Extension: New MUC (https://xmpp.org/extensions/inbox/new-muc.html) * UPDATED: XEP-0449 (Stickers) * UPDATED: XEP-0463 (MUC Affiliations Versioning) * UPDATED: XEP-0503 (Server-side spaces) * Proposed XMPP Extension: TLS Channel-Binding Downgrade Protection (https://xmpp.org/extensions/inbox/tdp.html) 4) Items for voting a) Proposed XMPP Extension: Payment Required https://xmpp.org/extensions/inbox/payment-required.html b) Proposed XMPP Extension: Emoji Markup https://xmpp.org/extensions/inbox/emoji-markup.html c) Proposed XMPP Extension: New MUC https://xmpp.org/extensions/inbox/new-muc.html d) Proposed XMPP Extension: TLS Channel-Binding Downgrade Protection https://xmpp.org/extensions/inbox/tdp.html e) XEP-0045: Fix examples for messages from the room itself https://github.com/xsf/xeps/pull/1537 5) Pending votes none See the spreadsheet of doom: https://docs.google.com/spreadsheets/d/14gy_nhuTnqlktakJfLZ2Mc-jblSaG0na0Kh… 6) Date of Next 7) AOB 8) Close

4 days, 1 hour

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Proposed XMPP Extension: TLS Channel-Binding Downgrade Protection

by Daniel Gultsch

The XMPP Extensions Editor has received a proposal for a new XEP. Title: TLS Channel-Binding Downgrade Protection Abstract: This specification provides a way to secure the SASL and SASL2 SCRAM handshakes against channel-binding downgrades through TLS version downgrades. URL: https://xmpp.org/extensions/inbox/tdp.html The Council will decide in the next two weeks whether to accept this proposal as an official XEP.

4 days, 1 hour

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UPDATED: XEP-0503 (Server-side spaces)

by Daniel Gultsch

Version 0.3.0 of XEP-0503 (Server-side spaces) has been released. Abstract: This document defines an XMPP protocol to cluster several groupchat rooms together. Changelog: * Fix pubsub node field name in room disco info. * Specify how to attach images (avatar and banner) to a space. (nc) URL: https://xmpp.org/extensions/xep-0503.html Note: The information in the XEP list at https://xmpp.org/extensions/ is updated by a separate automated process and may be stale at the time this email is sent. The XEP documents linked herein are up-to- date.

4 days, 1 hour

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UPDATED: XEP-0463 (MUC Affiliations Versioning)

by Daniel Gultsch

Version 0.2.0 of XEP-0463 (MUC Affiliations Versioning) has been released. Abstract: This specification provides a way to reduce the amount of queries necessary to stay up-to-date with affiliations in a MUC room. Changelog: Use a dedicated child element of <x/> rather than namespaced attributes. (lmw) URL: https://xmpp.org/extensions/xep-0463.html Note: The information in the XEP list at https://xmpp.org/extensions/ is updated by a separate automated process and may be stale at the time this email is sent. The XEP documents linked herein are up-to- date.

4 days, 1 hour

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UPDATED: XEP-0449 (Stickers)

by Daniel Gultsch

Version 0.2.0 of XEP-0449 (Stickers) has been released. Abstract: This specification provides a protocol to send stickers and to create and share sticker packs. Changelog: Make pack attribute explicitly a MAY. Add more details about sending/receiving stickers without a sticker pack. (lmw) URL: https://xmpp.org/extensions/xep-0449.html Note: The information in the XEP list at https://xmpp.org/extensions/ is updated by a separate automated process and may be stale at the time this email is sent. The XEP documents linked herein are up-to- date.

4 days, 1 hour

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HTTP file upload and administrative boundaries

by Dave Cridland

Hi all, Some of the work I'm dealing with has the requirement that clients belonging to their organisation shouldn't access arbitrary HTTP endpoints outside their administrative boundary. I think this is a reasonable requirement. As an example, if A(a)a.example wants to send a file to B(a)b.example, A uploads to their own server, which: * Might (or might not) perform virus scanning, and * Might (or might not) log IP addresses and other activity, and * Might (or might not) expire the file sooner than B's organisation's retention policy. Some of these "might (or might not)" cases are probably specific to enterprise cases, but others are more general and apply to consumer/private messaging too. What I'd like to explore therefore is whether we could have B's server pull a copy of the file for B to access, processing and retaining it as B's organisation requires. But, and here lies my problem, I have literally no idea how to go about this without disruption to the generally working case of HTTP upload. Anyone got any ideas? Dave.

1 week, 2 days

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GC3 in 2026

by Matthew Wild

Hi folks, As promised in another thread, I'm posting a round-up of "GC3" resources. But first, I'll summarize what this is about for people who missed the summits/sprints where it was discussed. The idea grew, from discussions with a few people, that it would be good to level up group chats in XMPP, without breaking significantly with the extremely entrenched MUC protocol. In fact, we have already extended MUC (XEP-0045) in various ways, both by updating XEP-0045 itself and through various add-on XEPs in recent years, some with relatively rapid adoption (XEP-0421), and others not so rapid (yet?). There has been vague occasional talk of "MUC 2" for a very long time (since before MIX), mostly various isolated ideas for improvements. I wanted to try and finally glue some of these ideas together, without necessarily "stealing" the title as an official MUC successor, so "GC3" became a working title. Shortly after I'd started gathering this together, we held a sprint in the UK. A lot of that sprint ended up being reviewing the GC3 wishlist, priorities, eliminating some bad ideas, and clarifying some possible approaches. The slides of the GC3 presentation I gave at Summit 27, a few months later, are here: https://matthewwild.co.uk/uploads/xmpp-gc3-jan-2025.pdf The main GC3 notes, including feedback from the sprint and summit, are available here: https://pad.nixnet.services/s/7xKNOKxxE In addition to the notes, there have been a couple of partial attempts at turning it into something more like a specification. This one by Jonas: https://pad.nixnet.services/s/yu7drWpml This one by Kev: https://github.com/swift/protoxeps/blob/master/gc3.md Both these are missing some things, they probably overlap in some areas and conflict in others. But definitely together they form the basis of anything that would become a GC3 XEP. Apart from this, Kev also produced some additional related documents: - https://github.com/swift/protoxeps/blob/master/acl.md - https://github.com/swift/protoxeps/blob/master/related-entities.md These were spawned from GC3 discussions, but could certainly stand as XEPs in their own right. I don't want to speak for Kev, but I assume if there is sufficient interest then he would be willing to work further on these and get them submitted, or have someone else help to do so. Okay, that's the status of documentation. Partly because of the numerous ideas floating around, I also wanted to work on at least a rough prototype implementation of at least some core parts of the code. Just to try out the approach and prove it can work. I know that implementation isn't required by the XSF in order to have an experimental XEP. However, faced with the decision between spending time on writing a GC3 XEP, and figuring out if it can even be implemented, I personally chose to prioritize the latter. This isn't any kind of statement about whether or not there should be a GC3 XEP submitted at this stage, I *personally* just don't want to spend time writing such a broad XEP for a protocol that may need drastic changes as soon as anyone tries to implement it. I won't (and, anyway, can't) stop someone else with time and motivation from doing what they want (implementation or specification) with any of the "GC3" notes we've gathered. I presented them at the summit precisely with the hopes that everyone interested in the topic may do exactly that, so we can move the thing forward. After the summit presentation, I started making some necessary changes to the Prosody MUC code to allow us to accommodate some of the discussed GC3 features. Mainly internal refactoring of some APIs and data structures to make it more extensible and support chats where we have mixed MUC and GC3 clients. The only externally visible change in Prosody so far, is that I began implementing a participant list fetch protocol (behind an experimental feature flag). Ironically, it's one of the parts of the protocol we deemed during the sprint as high priority and yet we don't actually have a protocol for this written anywhere in the several "GC3"-related documents, yet. One of the features of such a protocol would be paging, e.g. using RSM. Prosody's implementation doesn't currently support this. I immediately ran into the problem that to support paging, the participant list needs to be ordered and stable. Currently Prosody stores affiliations and participants in unordered hash tables. Another thing that needs refactoring. Okay, that's the implementation update from me. Now, the status and future of GC3... It appears from discussions that multiple people have come to view me as having some kind of "ownership" over GC3. This was entirely unintended and very unfortunate. It's true (I think?!) that I picked the name, and I wrote the first draft of notes. However I think by now that between various discussions online and offline across and venues (regrettably not this list?), my personal contributions to the whole thing are quite outnumbered by others. Obviously if nobody else beat me to it, at some point writing a GC3 XEP was inevitably on my todo list. So I accept that I'm somehow the "default" person in a way - going to push this forward, eventually, if nobody else can/will. But it seems somehow this appeared as some kind of exclusivity, and this was likely due to poor communication on my part. In that regard, I am glad that Dave ignored this and broke the ice with the MUC2 proposal regardless, surfacing this whole issue. I like collaborating with smart folk, it's why I am here and why I do open-source. But I (and I'm not alone) have far more ideas, wishes and responsibilities than I have time to work on all at once. Sometimes this also means I get rather behind on emails, or that I might miss MUC discussions. If anyone else feels that I am somehow blocking them from doing what they want - I'm always willing to talk it over. And if that fails, please, just go ahead and do it. Now, finally, GC3 future... Realistically, I'm unlikely to change trajectory. I have a long list of stuff to do, and honestly, GC3 is outranked by various other priorities for the coming month or two at least. This means, I see the following possible outcomes: - MUC2 halts and nothing further happens until I finally get around to a GC3 XEP (nobody wants this) - MUC2 continues as a from-scratch parallel effort (not ideal in my opinion, but I can't and won't block such an effort, especially not if others think it's a good path) - MUC2 is at least informed and improved by the prior work on GC3, adopting as much or as little as deemed appropriate. Even if it ultimately adopts none of it, I think this would be a win. What I care about is that we arrive at a good MUC successor XEP with a good path to adoption. I will say it again just to be clear here: I don't care what it's called, or whose name(s) are on the document. Regards, Matthew

1 week, 2 days

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QUIC(ker)

by Dave Cridland

Hey all, Some of you have heard me talk about this at the Summit, but I'd like to revisit/reexamine our QUIC binding to improve performance of XMPP on low bandwidth. I'm not sure we'll get to this at the Summit, and there's not many who want to talk about it so I wondered if this summit topic could have been an email. (Except then we discussed it anyway) The primary concerns on low bandwidth - beyond sending fewer bytes on the wire - are round-trips and head-of-line blocking. I think XMPP has a good story on round-trips; we're down to very few during authentication and connection setup, and during normal messaging operation we don't worry about latency at all. Head-of-Line blocking, or HoL Blocking, is when - in our case - packet loss causes the stream to stall until the packet is retransmitted, which is at least a round-trip away - and can be more due to bandwidth-delay product. At the same time, we cannot eliminate this entirely (by, say, sending stanzas over UDP directly) because if we do that we lose the ordering. Out of order messages can be confusing, and lead to bad misunderstandings. The rules on this are in RFC 6120, and are rather more complicated than we normally worry about - normally, we just process everything on a strea, in order, and this does satisfy the rules. But the rules allow us to process stanzas in any order we like, as long as So, what I'm thinking is a way to use the additional channels in QUIC such that we open multiple channels on both C2S and S2S sessions, which would form part of the same virtual stream, and we can distribute messages such that we maintain ordering within messages where we need to, but allows us to out-of-order (and avoid HOL Blocking) messages sent between unrelated jids. This differs to the existing XEP, where each channel maps to a single XML Stream and XMPP session. Notes from the Summit: WEBTRANS would also be of interest, but "raw" QUIC has some advantages as well, so we probably want both with a uniform approach. So, my plan is to get an implementation together and a XEP. Anyone else interested? Dave.

1 week, 2 days

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