Rust 1.97 and 1.98 Land New Cargo Config, Algebraic Float Methods
Two point releases in six weeks bring default v0 symbol mangling, centralized warning control in Cargo, and opt-in floating-point optimizations that trade strict IEEE-754 semantics for speed.
The Rust project shipped two point releases six weeks apart this summer: 1.97.0 on July 9, 2026, and 1.98.0 on August 20. Both follow Rust's standard six-week release cadence, and between them they touch the compiler, Cargo, and the standard library.
Rust 1.97.0's biggest change is under the hood: the compiler now defaults to the "v0" symbol-mangling scheme instead of the legacy scheme based on the old Itanium C++ ABI. Symbol mangling is how the compiler encodes type and path information into the names linkers and debuggers actually see — v0 has been available as an opt-in for years, and making it the default closes out a long-running source of ambiguity in tools that parse Rust symbol names.
1.97.0 also stabilizes two Cargo configuration options: build.warnings lets a team set warning behavior — deny, allow, or warn — centrally, including via a CARGO_BUILD_WARNINGS environment variable, instead of editing every crate's lint attributes to enforce it in CI. A second option, resolver.lockfile-path, lets a project point dependency resolution at a lockfile outside its default location.
Rust 1.98.0's headline addition is a set of "algebraic" floating-point methods on f32 and f64 covering add, subtract, multiply, divide, and remainder. Ordinary floating-point math in Rust follows strict IEEE-754 semantics, which blocks the compiler from applying real-number algebraic optimizations like reassociation because they can change the result. The new algebraic methods opt into those optimizations explicitly, trading some precision guarantees for speed in numerics-heavy code that can tolerate it.
1.98.0 also adds a standardized format_into method for integer-to-string formatting, benchmarked on par with the long-popular third-party itoa crate — likely to reduce how often projects reach for that dependency going forward — along with new lints, invalid_runtime_symbol_definitions and suspicious_runtime_symbol_definitions, aimed at catching libc-shaped symbol redefinitions like memcmp or strlen before they cause runtime corruption.
Both releases are documented in full, including the complete stabilized-API list, on the official Rust blog.