Updating from 3.3.12 to 4.0.0 breaks our production deployment

[Glinkis]

After upgrading from 3.3.12 to 4.0.0, we get 404 for our index.html page.
We're using serve inside a docker container to serve our app in production.
If I do a local build, and run serve, everything works as expected.

Our dockerfile looks like this:

FROM node:12.16

# Copy only the files relevant to the installation
COPY ./yarn.lock /
COPY ./package.json /
COPY ./packages/babel/package.json /packages/babel/package.json
COPY ./packages/webapp/package.json /packages/webapp/package.json
COPY ./packages/shared/package.json /packages/shared/package.json

# Install dependencies recursively for all packages
RUN yarn install --frozen-lockfile

# Copy the rest of the directory
COPY ./ /

ARG NODE_ENV
ENV NODE_ENV=$NODE_ENV
ARG API_URL
ENV API_URL=$API_URL

WORKDIR /packages/webapp

RUN export NODE_ENV=$NODE_ENV && export API_URL=$API_URL && yarn build

EXPOSE 8080

CMD ["yarn", "serve"]

The "serve" script is "serve": "serve -l 8080 -c ../serve.json",

And the serve config like this:

{
  "public": "dist",
  "directoryListing": false,
  "rewrites": [
    {
      "source": "/static/**",
      "destination": "/static"
    },
    {
      "source": "/**",
      "destination": "/index.html"
    }
  ]
}

[alexander-akait]

Sorry don't know, I don't know what your configuration mean, for running serve you need write webpack serve, we never support json config in this format

[Glinkis]

I wrote that we're using the serve package, not webpack serve. If you're going to answer, please read the full description.

[alexander-akait]

Sorry, serve is not related to webpack-cli, so I don't know why it does not work, if you want to help, please use the issue template and describe your problems, Updating from 3.3.12 to 4.0.0 breaks our production deployment is not help to solve your problem

[Glinkis]

I thought I described my problem quite thoroughly. I'm not sure what else to add?

[alexander-akait]

@Glinkis please create minimum reproducible test repo, I don't know what your Docker file do

[Glinkis]

It seems my issue was that the --env flag was changed in version 4. So I fixed it by following the advice in #1216