This seems like self promotion. The medium article is written by a competitor to signal. Someone should probably check out their source code. Edit: apparently

This seems like self promotion. The medium article is written by a competitor to signal. Someone should probably check out their source code. Edit: apparently it’s a paid SAAS. I don’t think that they have released the server source code. It’s seems like their protocol will remain secure with a compromised server, but their criticisms of signal are weak and motivated by greed. Honestly, I don’t know if this is a hit piece on signal or themselves.