- The Rust‑based Astro compiler is now default and the Go compiler plus its experimental flag are removed, causing breaking API changes.
- HTML compression now defaults to JSX rules and the markdown processor switches to satteri; @astrojs/db and several deprecated astro:transitions APIs are removed, requiring code updates.
- Adds background dev‑server management for AI agents, stabilizes advanced routing and route caching, and makes the custom logger feature generally available.