# Vitest v4.0.6 — Release & Upgrade Intelligence
- **Product:** Vitest (https://vitest.dev)
- **Version:** v4.0.6
- **Released:** Oct 31, 2025
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/vitest/updates/v4.0.6/

## Executive Summary (TL;DR)
Vitest v4.0.6. Source highlight:    🐞 Bug Fixes

## Bug Fixes
- Don't merge errors with different diffs for reporting &nbsp;-&nbsp; by @hi-ogawa in https://github.com/vitest-dev/vitest/issues/8871 <samp>(3e19f)</samp>
- Do not throw when importing a type from an external package &nbsp;-&nbsp; by @sheremet-va in https://github.com/vitest-dev/vitest/issues/8875 <samp>(7e6c3)</samp>
- Improve spying types &nbsp;-&nbsp; by @sheremet-va in https://github.com/vitest-dev/vitest/issues/8878 <samp>(ca041)</samp>
- Reuse the same environment when `isolate` and `fileParallelism` are false &nbsp;-&nbsp; by @sheremet-va in https://github.com/vitest-dev/vitest/issues/8889 <samp>(31706)</samp>
- Support module tracking &nbsp;-&nbsp; by @sheremet-va in https://github.com/vitest-dev/vitest/issues/8877 <samp>(9e24a)</samp>
- Ensure setup files are re-evaluated on each test run &nbsp;-&nbsp; by @yjaaidi in https://github.com/vitest-dev/vitest/issues/8883 and https://github.com/vitest-dev/vitest/issues/8884 <samp>(f50ea)</samp>