Rust 1.89 is now released, expanding x86 and x86/x86_64 platform support with new processor instructions and features, including additional AVX-512 intrinsics. The target_feature attribute adds support for SHA512, SM3, SM4, KL, and WIDEKL, giving developers better access to modern CPU capabilities directly from Rust code.
Full changelog: https://blog.rust-lang.org/2025/08/07/Rust-1.89.0/
[T]he x86_64-apple-darwin target moves to Tier-2 due to Apple and GitHub reducing x86_64 macOS support
What does that mean? How can GitHub reduce x86_64 support in Rust?
Seems to be justification according to their changelog. (Wish the site would just link to that) I’m assuming they were going to do it, anyway, now that Apple has pretty much phased out x86 support, and Github’s discontinuation was just kinda put the final nail in the coffin.
Yeah, feels a little bit early when I know some devs in my company that still have x86 Macbooks, but I guess, it’s not like bugs will show up immediately, so we’ll see how that goes…
https://doc.rust-lang.org/nightly/rustc/platform-support.html
Tier 1 targets can be thought of as “guaranteed to work”. The Rust project builds official binary releases for each tier 1 target, and automated testing ensures that each tier 1 target builds and passes tests after each change.
https://doc.rust-lang.org/nightly/rustc/target-tier-policy.html#tier-1-target-policy
The target must build and pass tests reliably in CI, for all components that Rust’s CI considers mandatory.
Github is removing support for CI on that target, and since that’s a requirement for Tier 1 support the target has to be downgraded.
