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

Quick fix

Downgrade your autoprefixer to version 9, use

"autoprefixer": "^9.0.0"

in your dev dependencies.

More details

PostCSS was updated to version 8, however, PostCSS CLI has not yet been updated to handle PostCSS plugins which use the new PostCSS 8+ API. Autoprefixer uses the new PostCSS 8 API since version 10.

This is documented under known issues in the PostCSS GitHub page.

Once PostCSS CLI is updated to handle plugins that use the new PostCSS 8+ API, this will likely not be an issue. But until then, you may need to downgrade some PostCSS plugins to avoid errors.

Answer 2

"dependencies": {
    "autoprefixer": "^9.8.6",
    "postcss": "^8.0.0",
    "postcss-cli": "^8.1.0",
    "tailwindcss": "npm:@tailwindcss/postcss7-compat@^2.0.2",
},

Dependecies object and version can be modified directly in the package.json file and it work

Answer 3

These steps worked for me. This was from github

npm uninstall tailwindcss postcss autoprefixer
npm install tailwindcss@latest postcss@latest autoprefixer@latest

npx tailwindcss init -p

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

Answer 4

For Next.js 10 you just have to do

npm install tailwindcss@latest postcss@latest autoprefixer@latest

Source This issue here

Answer 5

the following combo works as of Oct 2020

  ...
  "dependencies": {
    "autoprefixer": "^9.8.6",
    "postcss-cli": "^8.1.0",
    "tailwindcss": "^1.9.2"
  }

Answer 6

I am not sure about this but can you try installing postcss as a dependency?

npm i postcss