# Tailwind CSS v4.3.4 — Release & Upgrade Intelligence
- **Product:** Tailwind CSS (https://tailwindcss.com)
- **Version:** v4.3.4
- **Released:** Nov 02, 2026
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/tailwind/updates/v4.3.4/

## Executive Summary (TL;DR)
Tailwind CSS v4.3.4 introduces `@tailwindcss/turbopack` for Next.js Turbopack integration alongside extensive fixes for template parsing, canonicalization, and bundler watch modes. This patch release resolves crashes in Vite's `bundledDev` mode, fixes code signing on macOS binaries, and improves `group-*` and `peer-*` style invalidation performance.

## New Features
- Added `@tailwindcss/turbopack`, a Turbopack loader for using Tailwind CSS with Next.js.

## Improvements
- Improved style invalidation performance for `group-*` and `peer-*` variants.
- Optimized watch mode by skipping ignored directories during glob generation instead of scanning their contents.
- Expanded arbitrary value length parsing to recognize viewport units (`dvmin`, `svi`) and font-relative units (`cap`, `rex`).
- Enhanced canonicalization logic to convert arbitrary breakpoint and container queries to named equivalents (e.g., `max-[64rem]:flex` to `max-lg:flex`).

## Bug Fixes
- Fixed binary code signing for standalone macOS binaries to prevent crashes on launch.
- Ensured `@tailwindcss/turbopack` and `@tailwindcss/webpack` rebuild when input CSS files change.
- Prevented `@tailwindcss/vite` from crashing under Vite's experimental `bundledDev` mode and stopped full-page reloads for non-module files.
- Ensured `@tailwindcss/oxide` falls back to WASM on platforms without native bindings.
- Fixed candidate extraction for Ruby `%w` and `%W` literals and complex syntax in Pug, Slim, and Haml templates.
- Fixed CSS parser handling for unclosed semicolons, comments ending in `\*/`, `!important` within strings, and nested `@scope` semantics.

## Upgrade Command
```bash
npm install --save-exact tailwindcss@4.3.4
```