# What changed in @stryker-mutator/vitest-runner

> 13 changes in @stryker-mutator/vitest-runner 9 to 10 from its official release notes, upgrade guides and advisories: 2 breaking, 2 new APIs and options. Each one cited. Sources checked 2026-10-25. HTML: https://unstale.sh/npm/@stryker-mutator/vitest-runner/

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

## @stryker-mutator/vitest-runner 10

### Breaking changes

- Node.js 20 is no longer supported; Node.js 22 or higher is required. (10.0.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#1000-2026-08-14)

### New APIs and options

- Configure the Vitest pool used to run tests; defaults to threads. The vmForks pool is unsupported by Vitest versions below 1.0.0. (10.1.0) — [docs](https://stryker-mutator.io/docs/stryker-js/vitest-runner)

### Fixes and other changes

- Fixes noisy warnings about Vitest options and setup files. (10.0.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#1000-2026-08-14)

## @stryker-mutator/vitest-runner 9

### Breaking changes

- The Vitest runner now supports Vitest v2 or higher. (9.0.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/HEAD/packages/vitest-runner/CHANGELOG.md)

### New APIs and options

- Adds an option to limit which tests are executed. (9.5.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#951-2026-02-02), [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#950-2026-01-30)

### Tooling

- The Vitest runner now supports Vitest fixtures created with test.extend. (9.5.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#951-2026-02-02), [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#950-2026-01-30)
- Adds support for Vitest 4. (9.4.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#940-2025-11-23)
- The Vitest runner now supports Vitest 3 browser mode. (9.0.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/HEAD/packages/vitest-runner/CHANGELOG.md)

### Fixes and other changes

- Fixes mutant hitcount and coverage in the Vitest runner for Vitest 4.1. (9.6.1) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#961-2026-04-10)
- Fixes the dual instance problem with Vitest plugins. (9.5.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#951-2026-02-02), [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#950-2026-01-30)
- Fixes the EBUSY warning on Windows when concurrency is 2 or greater. (9.5.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#951-2026-02-02), [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#950-2026-01-30)
- Detects suite-level failures when a test is skipped, so those failures are not missed. (9.4.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/cb3bd8fe25d5215422c9b632357062d3a43fcf92/packages/vitest-runner/CHANGELOG.md#940-2025-11-23)
- The Vitest runner ensures that test failure screenshots are not produced. (9.0.0) — [release notes](https://github.com/stryker-mutator/stryker-js/blob/HEAD/packages/vitest-runner/CHANGELOG.md)