Highlights include Sliding Sync (instant login/launch/sync), Native OIDC (industry-standard authentication), Native Group VoIP (end-to-end encrypted large-scale voice & video conferencing) and Faster Joins (lazy-loading room state when your server joins a room).
I won’t need to develop anything in response, because an open-standard (IETF) protocol for federated instant communications already existed long before Matrix, and as far as I can tell, from my experience of having administered XMPP and Matrix servers for hundred of users, nothing about Matrix, its design and its implementations makes it more desirable, more reliable, more resilient or more “future proof” than what XMPP came-up with a decade earlier.
And I am aware that I sound like an old man yelling at clouds, I take comfort in the fact that more and more technically-versed people who look behind the marketing and buzz get to see what I know from experience: https://telegra.ph/why-not-matrix-08-07
I think most of the criticism on Telegraph regarding how Matrix handles rooms and events are addressed by the work behind linearized matrix: https://www.qwant.com/?l=en&q=linearized+matrix+messaging&t=web
Since its inception, Matrix has always been “months away” from cracking this very problem, I won’t hold my breath for this one, not after 10 years of kicking the same can down the road.