Announcing Rust 1.99.1

# Announcing Rust 1.99.1 | Rust Blog Source: [https://blog.rust-lang.org/2026/10/15/Rust-1.99.1/](https://blog.rust-lang.org/2026/10/15/Rust-1.99.1/) The Rust team has published a new point release of Rust, 1\.99\.1\. Rust is a programming language that is empowering everyone to build reliable and efficient software\. If you have a previous version of Rust installed via rustup, getting Rust 1\.99\.1 is as easy as: ``` rustup update stable ``` If you don't have it already, you can[get`rustup`](https://www.rust-lang.org/install.html)from the appropriate page on our website\. ## What's in 1\.99\.1 Rust 1\.99\.1 fixes the following regressions from prior releases: - [Missing symbol`wcslen`](https://github.com/rust-lang/rust/issues/163614): Some Rust targets were getting link errors for missing`wcslen`, and that function is now present in Rust's compiler\-builtins library as a fallback\. The LLVM`loop\-idiom\-wcslen`pass may introduce calls to`wcslen`as an optimization, and some Rust targets did not have that function readily available in`libc`or elsewhere\. The UEFI targets in particular were broken for any project using`std`, as some of these calls were introduced in the precompiled standard library, but the issue was also reproducible for similar user code patterns\. - [Miscompilation of FFI`bool`return values on x86\_64](https://github.com/rust-lang/rust/issues/163911): Rust functions returning`bool`through FFI could leave bits 1\-7 of the return register unspecified, causing callers to observe raw values other than`0`or`1`\. This return type is now marked for zero\-extension again, as required by the ABI\. - [`rust\-lld`failed to load`libLLVM`on macOS](https://github.com/rust-lang/rust/issues/163947): This linker could fail to run if the compiler was invoked without the`rustup`proxy, as there was no direct setting for the appropriate library search path\. Now`rust\-lld`is built with an`rpath`entry for the directory containing`libLLVM\.dylib`\. If you'd like to help us out by testing future releases, you might consider using the beta \(`rustup default beta`\) and nightly \(`rustup default nightly`\) channels locally and in your CI\. Please[report](https://github.com/rust-lang/rust/issues/new/choose)any bugs you might come across\! ### Contributors to 1\.99\.1 Many people came together to create Rust 1\.99\.1\. We couldn't have done it without all of you\.[Thanks\!](https://thanks.rust-lang.org/rust/1.99.1/)