Twitter co-founder Jack Dorsey has announced the launch of "Bitchat," a decentralized chat application based on a Bluetooth Mesh network that supports end-to-end encryption and multi-hop relay communication, enabling offline peer-to-peer chat without the internet. The project focuses on an IRC-like communication experience, emphasizing privacy protection and local message transmission. It is now available on TestFlight and open-sourced on GitHub. [Wu Shuo]