Ferrocene 24.05.0 now available for purchase

Published on 3 min read
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A Rust compiler toolchain for safety- and mission-critical environments.

    We’ve got major updates: We've qualified Ferrocene 24.05.0 based on Rust 1.76.0 and CriticalUp 1.0.0: Ferrocene's installer and toolchain manager. And last, but not least: Ferrocene can now be purchased online as an individual license.

    Ferrocene is a mission- and safety-critical downstream distribution of the main Rust compiler. It is ISO 26262 and IEC 61508 qualified to the highest levels of safety (ASIL D and SIL 4, respectively). Other standards are to follow. Ferrocene is the fully open-source safety-critical Rust compiler and 100% compatible with the main Rust compiler, allowing you to work seamlessly with both the compiler distributed by the Rust project and the Ferrocene toolchain.

    What’s new in Ferrocene 24.05.0

    Ferrocene 24.05.0 expands the scope of our qualified toolchain, by including the x86-64 Linux target and upgrading Rust from 1.68.2 to 1.76.0. This will bring long-awaited features like the C-unwind ABI and async functions and returning impl Trait in traits to safety-critical users.

    In this release we are also including a preview of some features that are not yet qualified: support for the Armv7E-M and WASM targets, and the Clippy, rustfmt, rust-analyzer and rust-demangler tools.

    Ferrocene 24.05.0 comes with two years of updates (until May 2026) and is qualified for ISO 26262 and IEC 61508. See the release notes for the full list of changes included in this release.

    Introducing the CriticalUp toolchain manager

    While it was always possible to install Ferrocene manually on your system, Rust developers expect better from their tools, thanks to the excellent work done by the Rust project on the rustup toolchain manager.

    Along with the Ferrocene 24.05.0 release, we're introducing CriticalUp 1.0.0, the first release of the Ferrocene installer. CriticalUp allows installing multiple versions of Ferrocene for each of your projects, and easily switching between them. This enables developers to easily install Ferrocene on their machines, and use different Ferrocene versions in each project.

    Once you install CriticalUp and you authenticate with your Ferrocene account, you can create a criticalup.toml file in your project describing the release you want:

    manifest-version = 1
    release = "stable-24.05.0"
    packages = [

    Once the file is in your project, you can run criticalup install to fetch and install the requested release. At that point, invoking criticalup run rustc or criticalup run cargo will automatically use the Ferrocene version you just installed.

    Check out the CriticalUp documentation to learn more.

    Available for purchase today

    When we launched Ferrocene 23.06.0 last year, the only way to purchase it was to get in touch with our sales team and had a minimum order of 10 licenses. Since then we've been hard at work to enable everyone to purchase Ferrocene on their own.

    Each seat in the Ferrocene individual plan costs €25/month or €240/year, and grants access to all supported versions of Ferrocene (current and future) and basic support via email.

    Starting today you can get a copy of Ferrocene at with our new Individual plan. Premium support and custom contracts are still available for enterprises, if you are interested please contact us.

    Fully open source

    When we open sourced Ferrocene last year, we were only able to publish the source code of our main branch and not the source code of the Ferrocene 23.06.0 release. Since then, we lifted the limitations we have and we're proud that the full source code of the new Ferrocene 24.05.0 release is available on GitHub along with the source code of our main branch.

    Along with this, the rendered version of the documentation for our main branch is always available at, including all of our qualification documents.

    More to come!

    While today we are releasing Ferrocene 24.05.0, we’re already at work to prepare our next release. We can already share that the next Ferrocene release will include preview support for developing on Windows and macOS, and support for compiling Armv7-R and Armv8-R code!

    If you are a Ferrocene customer, you can gain early access to the next release in our “nightly” channel, available in the Ferrocene download portal and via CriticalUp.

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