# Tailwind CSS v4.0.1 — Release & Upgrade Intelligence
- **Product:** Tailwind CSS (https://tailwindcss.com)
- **Version:** v4.0.1
- **Released:** Jan 29, 2025
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/tailwind/updates/v4.0.1/

## Executive Summary (TL;DR)
Tailwind CSS v4.0.1. Source highlight: Include `:open` pseudo-class in existing `open` variant (#15349)

## New Features
- Include `:open` pseudo-class in existing `open` variant (#15349)

## Bug Fixes
- Remove invalid `min-w/h-none` utilities (#15845)
- Discard CSS variable shorthand utilities that don't use valid CSS variables (#15738)
- Ensure font-size utilities with `none` modifier have a line-height set e.g. `text-sm/none` (#15921)
- Ensure font-size utilities with unknown modifier don't generate CSS (#15921)
- Don’t suggest font weight utilities more than once (#15857)
- Suggest container query variants (#15857)

## Upgrade Command
```bash
npm install --save-exact tailwindcss@4.0.1
```