@wojtek I've looked over OMEMO specification, PubSub specification and discussed that with Daniel and even if we would remove our OMEMO keys (Beagle/Siskin) there may still be some other key (or will be published when any other OMEMO compatible client published its key on your account). And if there is at least one key another side may try to send encrypted message to you.

At this point, I'm wondering if we should not add a server side feature, which would just respond with an error on incoming OMEMO message and at the same time would not allow any of your clients to publish OMEMO keys at your PEP service.

What do you think? Simple blocking and responding with an errpr as I've suggested would also work but it would not enforce that behavior and would store those messages in MAM archive.

Maybe we could set max_items for OMEMO nodes? That should effectively prevent anyone from publishing there?

Though not sure anymore it we want to fight it.

@wojtek I think, we do not want to do that. At least not now and it could make some issues with other clients not knowing how to reenabled OMEMO.

How about blocking any OMEMO message and responding that we do not want "encrypted" communication?

tbh I'm not sure now. That could send bad-PR (look, they are gains encryption, boo-hoo). I don't see any straightforward way of preventing using OMEMO for now…

In this case, I'm closing the issue with "Won't Fix" resolution.