# Tailwind CSS v4.0.15 — Release & Upgrade Intelligence
- **Product:** Tailwind CSS (https://tailwindcss.com)
- **Version:** v4.0.15
- **Released:** Mar 20, 2025
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/tailwind/updates/v4.0.15/

## Executive Summary (TL;DR)
Tailwind CSS v4.0.15. Source highlight: Fix incorrect angle in `-bg-conic-*` utilities (#17174)

## Bug Fixes
- Fix incorrect angle in `-bg-conic-*` utilities (#17174)
- Fix `border-[12px_4px]` being interpreted as a `border-color` instead of a `border-width` (#17248)
- Work around a crash in Safari 16.4 and 16.5 when using the default Preflight styles (#17306)
- Pre-process `<template lang="…">` in Vue files (#17252)
- Ensure that all CSS variables used by Preflight are prefixed (#17036)
- Prevent segfault when loaded in a worker thread on Linux (#17276)

## Upgrade Command
```bash
npm install --save-exact tailwindcss@4.0.15
```