XMPP

Well, there is something mentioned about latest version of omemo:

OMEMO doesn’t attempt to provide even the vaguest rationale for its design choices, and appears to approach cryptography protocol specification with a care-free attitude.

To put it mildly, this is the wrong way to approach cryptography

...

Because there is no rationale given for this sudden square-root reduction in security against existential forgery attacks, we kind of have to fill in the gaps and assume it was because of some kind of performance or bandwidth considerations.

But even that doesn’t really justify it, does it?

You’re only saving 16 bytes of bandwidth by truncating the MAC. Meanwhile, the actual ciphertext blobs are being encoded with base64, which adds 33% of overhead.

For any message larger than 48 bytes, this base64 encoding will dominate the bandwidth consumption more than using the full HMAC tag would.

...

Is truncating the HMAC tag to to 128 bits still secure? According to Signal, yes, it is. And I offer no disagreement to Signal’s assessment here.

The problem is, as I’ve said repeatedly, OMEMO’s specification makes no attempt to justify their design decisions.

Then on one of the comments, there's an interesting comment on something signal has mentioned it's working on quantum resistance, that it's no clear is something omemo will support, and even less when clients might adopt if eventually available:

Indeed quite often someone compares the two protocols and implies OMEMO is as mature as the current state of the art Signal protocol. Allow me to throw in the emerging post-quantum support that Signal is adding or already has in libsignal.

Somehow is implied on the comment that omemo is immature compared to libsignal...

At any rate, dino uses libsignal-protocol-c (on Artix/Arch 2.3.3), not libomemo, and conversations uses libaxolotle-java (according to the "about" section in the settings). So somehow using signal library underneath. Although I have no idea how up to date with regards to the signal library those might be (though the axolotl dependency on conversations allows to think it's outdated). And for conversations the author mentions:

To be clear: These aren’t separate dependencies that Conversations pulls in to implement plugin supports. They’re first-party cryptographic implementations all within this Android app’s codebase.

I guess by 1st party the author means like copy/paste the code (with local twists, which might be dangerous but perhaps necessary) to have a local version of the libraries. This sounds like a non version related criticism, but it's client related rather than protocol related, however the author mentions other clients are way worse, leaving no hope...

I don't see on dino an option to always use omemo BTW, not sure if dino just it implies omemo by default, but it doesn't have a way to force it. Perhaps a feature to ask dino developers...

At any rate, according the post there's little hope for xmpp + omemo. Which was actually something I was still hoping for, well, besides getting jami working at some point (but it has crypto issues on its own, including lack of auditing).