Download Wasmtime 41.0.0

41.0.0
Released 2026-01-20.
Added
- Support for {Future,Stream}Any in the component model has improved.
#12142
- Wasmtime has initial support for breakpoints and single-stepping with the
debug feature for guest programs.
#12133
- Wasmtime has begun adding a new Error type which is similar to
anyhow::Error but supports gracefully handling OOM. Wasmtime still uses
anyhow::Error but this will change in the future to wasmtime::Error which
will be a distinct type.
#12163
- An initial top-level crate for async-debugging guest programs has been added.
#12183
Changed
- Cranelift now optimizes redundant select + icmp instructions.
#12135
- Synchronous component model functions can no longer block before returning.
This implements a change in the upstream specification to the upcoming async
support in the component model which places stricter restrictions on
non-async functions and their ability to perform blocking operations.
#12043
- Frame iteration in debug mode now visits all activations which enables
seeing all frames from recursive wasm calls.
#12176
- Wasmtime now requires Rust 1.90.0 or later.
#12167
- Intra-component stream/future reads/writes are now allowed for simple data
types.
#12181
- The POLL callback code has been removed from the canonical ABI for async
functions and the waitable-set.poll function no longer yields.
#12182
- Guest-to-guest adapters injected by Wasmtime now have improved trapping error
messages.
#12215
Fixed
- #[derive(Lift)] for enums with exactly 256 cases has been fixed.
#12140
- With component-model-async support recursively calling a guest from a host
function has now been fixed.
#12152