Tor Project releases Arti 1.5 with new client features, relay backend work, and bug fixes

Arti 1.5.0, the latest release from the Tor Project’s Rust-based Tor implementation, delivers progress on several crucial client features. The update advances development of Counter Galois Onion encryption, improves path selection through the Conflux feature, and introduces enhancements for flow control, congestion control, and onion service proof of work. These updates aim to strengthen privacy, performance, and service reliability for users of the next-generation Tor implementation.

Alongside client-side improvements, this version includes substantial backend work to move Arti closer to supporting relay functionality. Relay support is foundational for Arti’s future as a fully featured Tor implementation. In terms of reliability, Arti 1.5.0 mitigates a longstanding issue that could prevent clients from completing the bootstrap process. Addressing this bug directly improves the initial connectivity experience for both new and existing users.

Following the Tor Project’s minimum supported Rust version policy, Arti 1.5.0 now requires Rust 1.85 or newer. This update aligns with upstream requirements and affects contributors and build environments. These changes are supplemented by various enhancements and additional bug fixes, further stabilizing the codebase.