tldr, it's snake oil. The company lies about its system being able act as a server without knowing anything about the users. The SimpleX clients don't route via Tor so the server will by definition know the IP addresses of the conversing parties. SimpleX claims to be the most metadata secure app, yet it fails to address the first issue of hiding IP addresses. Also a server has access to each IP addresses' social graph when they see to which target IPs they are forwarding packets. So much for metadata-free.
tldr, it's snake oil. The company lies about its system being able act as a server without knowing anything about the users. The SimpleX clients don't route via Tor so the server will by definition know the IP addresses of the conversing parties. SimpleX claims to be the most metadata secure app, yet it fails to address the first issue of hiding IP addresses. Also a server has access to each IP addresses' social graph when they see to which target IPs they are forwarding packets. So much for metadata-free.