# Vitest v5.1.0 — Release & Upgrade Intelligence
- **Product:** Vitest (https://vitest.dev)
- **Version:** v5.1.0
- **Released:** Nov 02, 2026
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/vitest/updates/v5.1.0/
## Executive Summary (TL;DR)
Vitest v5.1.0. Source highlight: 🚀 Features
## New Features
- Add `--last-failed` to run only failed tests - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11558 (82f63)
- Support `Temporal.Instant` and `Temporal.ZonedDateTime` in `vi.setSystemTime()` - by @Prajwal2246, **Prajwal2246**, **Claude Opus 5.5 (1M context)**, @hi-ogawa and **Codex (GPT-6)** in https://github.com/vitest-dev/vitest/issues/11321 (f150f)
- Introduce `--since-last-run` flag - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11516 (08bd9)
- Expose per-retry/repeat attempt result - by @hi-ogawa, **Codex (GPT-6)** and **Claude Opus 5.5 (1M context)** in https://github.com/vitest-dev/vitest/issues/11232 (21be4)
- Support fake timers for `node:timers` and `node:timers/promise` - by @hi-ogawa, **OpenCode** and **Codex (GPT-6)** in https://github.com/vitest-dev/vitest/issues/10899 (fbe97)
- Allow coverage providers to store data in fs module cache - by @AriPerkkio in https://github.com/vitest-dev/vitest/issues/11747 (54a2b)
## Improvements
- Reuse fsModuleCache in static collection - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11622 (1766c)
- Cache setup/mock resolves in reused workers - by @hi-ogawa and **Claude Opus 5.5 (1M context)** in https://github.com/vitest-dev/vitest/issues/11760 (5de10)
- Don't refetch warm modules in reused runners - by @hi-ogawa and **Claude Opus 5.5 (1M context)** in https://github.com/vitest-dev/vitest/issues/11761 (4f135)
- Map only first frame for trace locations - by @hi-ogawa and **Claude Opus 5.5 (1M context)** in https://github.com/vitest-dev/vitest/issues/11613 (a967d)
- Disable WebSocketServer's allowSynchronousEvents - by @nstepien in https://github.com/vitest-dev/vitest/issues/11794 (d4572)
- Istanbul to use `magic-string`+`rolldown` for instrumentation - by @AriPerkkio in https://github.com/vitest-dev/vitest/issues/11648 (2470b)
## Bug Fixes
- Rerun setup files after `--changed` filtering - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11621 (3a39c)
- Return the mock to concurrent imports - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11623 (1453b)
- Don't fail on console log pending at teardown - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11619 (a60b8)
- Reference chai types in every d.ts chunk - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11618 (fb150)
- Detect mock factory cycles that form later - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11642 (e9554)
- Skip fs module cache for typed import.meta.glob - by @sheremet-va in https://github.com/vitest-dev/vitest/issues/11666 (79501)