SimpleX Chat v5.8: Private Message Routing

"Private message routing is, effectively, a 2-hop onion routing protocol inspired by Tor design, but with one important difference - the first (forwarding) relay is always chosen by message sender and the second (destination) - by the message recipient.  In this way, neither side of the conversation can observe IP address or transport session of another."

https://www.nobsbitcoin.com/simplex-chat-v5-8/