6.6 “Kaiyuan”

@ai ai released this Dec 23, 2016 · 32 commits to master since this release

Emperor Xuanzong of Tang

This release uses Browserslist 1.5 and is focused on sharing browsers with babel-preset-env and create-react-app.


We know that many developers hate the current mess of config files in the project root.

With Autoprefixer 6.6 you can specify browsers in package.json to reduce config files:

  "private": true,
  "devDependencies": {
    "autoprefixer": "^6.6.0",
    "postcss": "^5.2.6"
  "browserslist": [
    "last 2 versions",
    "ie 9"

Note that we highly recommend specifying browsers in browserslist config or in package.json instead of Autoprefixer option. In this case many other tools will share browsers list, including Stylelint and babel-env-preset.


In most cases, you should use same browsers list for Autoprefixer in development and production. But right now Autoprefixer share browsers list with many other tools including babel-env-preset.

To improve development performance developers might want to use different target browsers in development.

So both Browserslist config now supports environments:

last 1 version

last 2 version
> 1%
  "private": true,
  "devDependencies": {
    "autoprefixer": "^6.6.0",
    "postcss": "^5.2.6"
  "browserslist": {
    "development": [
      "last 1 version"
    "production": [
      "last 2 version",
      "> 1%"

Autoprefixer will use env option, BROWSERSLIST_ENV or NODE_ENV to detect current environment.

Custom Browser Statistics

In addition to > 1% and > 1% in US, Browserslist supports > 1% in my stats to select popular versions according your visitors statistics.

To do it you need save JSON data from Google Analytics.

Autoprefixer 6.6 support standard name for this usage data file browserslist-stats.json and will load it automatically, without need to pass stats options.

It is especially useful if you share browsers with other tools without stats option support.