Angular 12 update issue: Unknown error from PostCSS plugin

Question

Hi after I ran "ng update @angular/core@12 @angular/cli@12" to upgrade from 11 to 12, and then "ng serve app" I keep getting the following error: "Unknown error from PostCSS plugin. Your current PostCSS version is 8.2.14, but postcss-preset-env uses 7.0.35. Perhaps this is the source of the error below."

What's my problem? No PostCSS in package.json. I don't know about it. Thanks in advance.

Answer 1

The issue seems to be related to the file .browserslistrc, renamed from browserlist during the upgrade migration. I resolved this issue by creating a new angular app, but only for the purposes of creating the default .browserslistrc file, and then copied that file to my upgraded app.

Answer 2

Update .browserlistrc to this:

last 1 Chrome version
last 1 Firefox version
last 2 Edge major versions
last 2 Safari major versions
last 2 iOS major versions
Firefox ESR
not IE 11 # Angular supports IE 11 only as an opt-in. To opt-in, remove the 'not' prefix on this line.