# Tailwind CSS v4.3.5 — Release & Upgrade Intelligence
- **Product:** Tailwind CSS (https://tailwindcss.com)
- **Version:** v4.3.5
- **Released:** Nov 06, 2026
- **Impact Score:** 3/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/tailwind/updates/v4.3.5/

## Executive Summary (TL;DR)
Tailwind CSS v4.3.5 delivers important bug fixes and performance improvements, notably enhancing canonicalization for projects using large functional variant sets. It also resolves color-mix parsing issues and addresses WebContainer file-watching stability for the WASI oxide engine.

## Improvements
- Canonicalization: improved performance in projects with many functional variant values (e.g., matchVariant plugins)

## Bug Fixes
- Prevent crashes or incorrect fallbacks for malformed color-mix(…) syntax lacking a color interpolation method
- Ensure @tailwindcss/oxide-wasm32-wasi loads properly instead of hanging in WebContainers or when using NAPI_RS_FORCE_WASI=error
- Remove incorrect 'as: "*.css"' configuration from @tailwindcss/turbopack README setup to prevent breaking CSS modules
- Ignore comments between top-level CSS rules rather than throwing errors or swallowing subsequent rules
- Ensure @tailwindcss/oxide-wasm32-wasi correctly detects changed and new source files after the initial scan
- Prevent TypeScript errors with skipLibCheck: false caused by unshipped module imports in @tailwindcss/node type declarations

## Upgrade Command
```bash
npm install --save-exact tailwindcss@4.3.5
```