# Tailwind CSS v4.3.3 — Release & Upgrade Intelligence
- **Product:** Tailwind CSS (https://tailwindcss.com)
- **Version:** v4.3.3
- **Released:** Jul 16, 2026
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/tailwind/updates/v4.3.3/

## Executive Summary (TL;DR)
Tailwind CSS v4.3.3. Source highlight: Support `--watch --poll[=ms]` in `@tailwindcss/cli` when filesystem events are unreliable or unavailable (#20297)

## Bug Fixes
- Support `--watch --poll[=ms]` in `@tailwindcss/cli` when filesystem events are unreliable or unavailable (#20297)
- Canonicalization: match arbitrary hex colors against theme colors case-insensitively (e.g. `bg-[#fff]` and `bg-[#FFF]` → `bg-white`) (#20298)
- Prevent Preflight from overriding Firefox's native `iframe:focus-visible` outline styles (#20292)
- Ensure `theme('colors.foo')` in JS plugins resolves correctly when both `--color-foo` and `--color-foo-bar` exist (#20299)
- Ensure fractional opacity modifiers work with named shadow sizes like `shadow-sm/12.5`, `text-shadow-sm/12.5`, `drop-shadow-sm/12.5`, and `inset-shadow-sm/12.5` (#20302)
- Parse selectors like `[data-foo]div` as two selectors instead of one (#20303)

## Upgrade Command
```bash
npm install --save-exact tailwindcss@4.3.3
```