# What changed in @tanstack/router-core

> 4 changes in @tanstack/router-core 1 from its official release notes, upgrade guides and advisories: 1 breaking. Each one cited. Sources checked 2026-10-19. HTML: https://unstale.sh/npm/@tanstack/router-core/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## @tanstack/router-core 1

### Breaking changes

- Returns the callback's own result instead of wrapping it in a promise, so synchronous throws now propagate synchronously. (1.171.36) — [release notes](https://github.com/TanStack/router/releases/tag/%40tanstack/router-core%401.171.36)

### Performance

- Generated script preloads now use low fetch priority and forward it into static Early Hints, so they no longer compete with render-blocking stylesheets, fonts, and images. (1.171.38) — [release notes](https://github.com/TanStack/router/releases/tag/%40tanstack/router-core%401.171.38)
- Reads a URL input without cloning it, reducing per-request work. (1.171.36) — [release notes](https://github.com/TanStack/router/releases/tag/%40tanstack/router-core%401.171.36)

### Fixes and other changes

- SSR reuses the parsed request location instead of repeating input rewrites, matches server routes against the app router's parsed pathname, and preserves encoded pathnames for server handlers and middleware. (1.171.37) — [release notes](https://github.com/TanStack/router/releases/tag/%40tanstack/router-core%401.171.37)