# Tailwind CSS v3.4.19 — Release & Upgrade Intelligence
- **Product:** Tailwind CSS (https://tailwindcss.com)
- **Version:** v3.4.19
- **Released:** Dec 10, 2025
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/tailwind/updates/v3.4.19/

## Executive Summary (TL;DR)
Tailwind CSS v3.4.19. Source highlight: Don’t break `sibling-*()` functions when used inside `calc(…)` (#19335)

## Bug Fixes
- Don’t break `sibling-*()` functions when used inside `calc(…)` (#19335)

## Upgrade Command
```bash
npm install --save-exact tailwindcss@3.4.19
```