See breaking changes in changelog:

https://github.com/webpack-contrib/css-loader/releases/tag/v7.0.0

Migration guide:

Before:

import style from "./style.css";

console.log(style.myClass);

After:

import * as style from "./style.css";

console.log(style.myClass);

Typescript migration:

Before:

declare module '*.module.css' {
  const classes: { [key: string]: string };
  export default classes;
}

After:

declare module '*.module.css' {
  const classes: { [key: string]: string };
  export = classes;
}