Arti 2.5.0 released: Stable Counter Galois Onion

Arti is our ongoing project to create a next-generation Tor implementation in Rust. We're happy to announce the latest release, Arti 2.5.0.

This release marks Counter Galois Onion as a stable feature and includes it in full feature builds. Likewise, Congestion Control is now enabled in default builds of Arti, increasing the overall speed without any further configuration.

Unfortunately, this release also comes with the disclosure of two medium-severity DoS security issues, TROVE-2026-024 as well as TROVE-2026-027, whose fixes are of course included within the release.

Additionally, this release continues our ongoing development towards using Arti as a relay and as a directory authority.

Another noteworthy change is that we've increased our minimum supported Rust version to Rust 1.91, released in October 2025.

Of course, this release also contains a number of bugfixes, cleanups, and improvements throughout various parts of the code base.

For full details on what we've done, including API changes, and for information about many more minor and less-visible changes, please see the CHANGELOG.

For more information on using Arti, see our top-level README, and the documentation for the arti binary.

Thanks to everybody who's contributed to this release, including 5225225, Neel Chauhan, hjrgrn, moumenalaoui, pryty26.

Also, our deep thanks to our sponsors for funding the development of Arti!