Matrix and meta data problems?

A friend joined me on Matrix and was sending me this link today. Side node: this article is over 4 years old.

I didn’t get it until I saw the amount of metatata on a server running matrix.
Matrix is federated (which is not peer to peer) and it’s ok that all is end-to-end encrypted, but all the metadata are shared cleartext with all the other matrix server . This means that one malicious server in the federated network can have access to the metadata conversation of other people

I have no idea how much this is true or not. Maybe it is just outdated since 2018 matrix was in an early stage of development. In first case I don’t trust it, but I want to know more. So I want to know your opinion and arguments, since some of you may know more.

This is probably a question to be asked at the Matrix HQ channel or by emailing

Also worth pointing out that Matrix is undergoing a major rewrite (see:, which means that anything from 2018 is probably meaningless.