Error: PostCSS plugin autoprefixer requires PostCSS 8. Update PostCSS or downgrade this plugin

Question

I am getting this error whenever I run npm start. I tried a couple of fixes but none of them work for me. I tried to change the version of autoprefixer to 9.8.6 but it didn\'t w

Answer 1

If you're having this problem and you're using Tailwind CSS v2, try this

npm uninstall tailwindcss postcss autoprefixer
npm install tailwindcss@npm:@tailwindcss/postcss7-compat postcss@^7 autoprefixer@^9

source: https://tailwindcss.com/docs/installation#post-css-7-compatibility-build

Answer 2

Ok, to me was fixed removing package-lock.json and installing:

"tailwindcss": "^1.8.10"
"postcss-cli": "^7.1.0"
"autoprefixer": "^9.7.5"

Answer 3

Based on documentation link are drop some support for old NodeJS and you must upgrade manually the packages. Example in my case for a project based on webpack need just to update those dependencies:

  "dependencies": {
    "autoprefixer": "^10.0.2",
    "postcss": "^8.1.7",
    "postcss-loader": "^4.0.4"
  }

So you do not need to downgrade autoprefixer :)

Answer 4

I had this problem with Laravel-mix 5 and PostCSS 8 and Tailwind 2.
With Laravel-mix 6 (beta at the moment) this was solved.

npm install laravel-mix@next --save-dev