# Vitest v4.1.9 — Release & Upgrade Intelligence
- **Product:** Vitest (https://vitest.dev)
- **Version:** v4.1.9
- **Released:** Jun 16, 2026
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/vitest/updates/v4.1.9/

## Executive Summary (TL;DR)
Vitest v4.1.9. Source highlight: Fix `importOriginal` with optimizer and query import [backport to v4] - by **Hiroshi Ogawa**, **David Harris**, **Codex**and **Vladimir** in https://github.com/vitest-dev/vitest/issues/10546 <samp>(a5180)</samp>

## Bug Fixes
- Fix `importOriginal` with optimizer and query import [backport to v4] - by **Hiroshi Ogawa**, **David Harris**, **Codex**and **Vladimir** in https://github.com/vitest-dev/vitest/issues/10546 <samp>(a5180)</samp>
- Wait for orchestrator readiness before resolving browser sessions [backport to v4] - by **Vladimir** and **Séamus O'Connor** in https://github.com/vitest-dev/vitest/issues/10555 <samp>(7fb29)</samp>
- Wait for iframe tester readiness before preparing  [backport to v4] - by **Vladimir** and **Séamus O'Connor** in https://github.com/vitest-dev/vitest/issues/10497 and https://github.com/vitest-dev/vitest/issues/10556 <samp>(fbc62)</samp>
- Hoist vi.mock() for vite-plus/test imports [backport to v4] - by **Hiroshi Ogawa**, **LongYinan**, **Claude Opus 4.8** and **Vladimir** in https://github.com/vitest-dev/vitest/issues/10548 <samp>(2c955)</samp>
- Prevent test run hang on worker crash  [backport to v4] - by **Ari Perkkiö** and **Jattioui Ismail** in https://github.com/vitest-dev/vitest/issues/10543 and https://github.com/vitest-dev/vitest/issues/10564 <samp>(934b0)</samp>