Even if they release up-to-date server code, we have no way to confirm that's the code that's running on their servers. People would then complain that they don't have shell access to the servers to ensure the code is what is expected.
Modern Intel chips support a feature called Software Guard Extensions (SGX). SGX allows applications to provision a “secure enclave” that is isolated from the host operating system and kernel, similar to technologies like ARM’s TrustZone. SGX enclaves also support a feature called remote attestation. Remote attestation provides a cryptographic guarantee of the code that is running in a remote enclave over a network.
https://signal.org/blog/private-contact-discovery/
But of course you need published source code and reproducible build.
Right now if you run the published server code and point the client certain features don't work. Doesn't that sound a little concerning ?