http://lainyubrp2aabmxhepbttfdbl53dct2inqifs42buvpf6w44uiitbeqd.onion/blog/matrix.html
E2EE is achieved in p2p chats and small groups only by invite. There used to be some problems with encryption, but after a while, the whole thing became stable, and I haven't seen funny "Message cannot be decrypted" in a long time.