Modern XMPP project discussion - 2025-08-10

What's the state of MLS in XMPP? Anyone working on that? It'd be nice to be able to have E2EE preserving bridges with Matrix. If some people rather use that, fine, whatever. I could still talk to them and have encryption. ^_^

Looking at the Matrix status page, it looks like they will actually get there: https://arewemlsyet.com/

Also, does MLS require support on the server in any form?

Someone™ is working on that, but I would be surprised if Matrix interop is going to happen that way.

erebion: larma promised an experimental xep til the end of the year in his last presentation

The MLS Talk started at 4:36:40 https://www.youtube.com/watch?v=8DLYl3-qVTk

> Also, does MLS require support on the server in any form? It was long since I read MLS specs but from what I remember the server requirements boil down to in-order message delivery (XMPP always did this) and publishing some stuff (read: XEP-0163, which is already needed for OMEMO) ↺

There is some minor change needed for 1:1 chats, which is why group chats are targeted first.

> The MLS Talk started at 4:36:40 https://www.youtube.com/watch?v=8DLYl3-qVTk I cannot view YouTube videos. Is this available elsewhere? ↺

It is mostly about mimi and surpisingly low on details. Not really worth it imho.

erebion: just to set expectations correctly: MLS won't enable E2EE-preserving bridges

MIMI might, but I'm not aware that anyone is actively working on that (on the XMPP or Matrix side)

MIMI is basically a whole new messaging protocol

s2s only though

Yes, so you would need an XMPP bridge to MIMI, and a Matrix bridge to MIMI

and then both could have some form of interoperability

But if history is anything to go by, it will be a far worse experience over such a bridge than native XMPP<->XMPP or Matrix<->Matrix

and then all XMPP features would need to be translated to whatever inner payload format you send over MIMI?

And likely any direct XMPP<->Matrix bridges

Zash: yes, and for E2EE-preserving, this (MIMI) has to be implemented in every client you use

Hm, did larma say in that talk what format it was? I'm guessing either https://datatracker.ietf.org/doc/html/rfc3860 or some profile of Matrix message syntax

or, was it CMS?

> erebion: just to set expectations correctly: MLS won't enable E2EE-preserving bridges Why, though, if both are using the same crypto? Just forward crypt text, would be what I've been imagining. ↺

and then you are limited to plain text messages only

What would stop me from just sending crypt text?

I can also put GPG sognatures in any file and copy them somewhere else.

Hm, sorry, "plain text" in this context is confusing.

I mean that more complex content like reactions, file transfers, stickers, anything more than just regular texting would not work.

But then thanks to limitations in Conversations database schema, that is basically what we have already.

> I mean that more complex content like reactions, file transfers, stickers, anything more than just regular texting would not work. Which would be fun, I just want to talk to people... Wothout slow Matrix clients on all my devices. ↺

*be fine

and then one day you want to put some descriptive text on your pictures and you can't and that's why ~XMPP~ MIMI will never be popular!