# Vitest v0.1.21 — Release & Upgrade Intelligence
- **Product:** Vitest (https://vitest.dev)
- **Version:** v0.1.21
- **Released:** Jan 18, 2022
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/vitest/updates/v0.1.21/

## Executive Summary (TL;DR)
Vitest v0.1.21. Source highlight: **ui:** ui improvements (#574) (730e354)

## New Features
- vi.mock can be called inside external libraries (#560) (4dbefb5)

## Bug Fixes
- **ui:** ui improvements (#574) (730e354)
- **vite-node:** stub `/@vite/client` by default (9ef5997)
- don't use string.replaceAll (#570) (833fb8a)
- rename `interpretDefault` option to `interopDefault` (53633b7)
- skip interop for esm (7bf0016)