anchor.diff:  # for performing pushes to production, and so this image is quite a bit larger
   # than strictly needed for just building Flutter apps.
   
  -# Last manual update 2020-10-05 (changing this comment will re-build image)
  +# Last manual update 2021-09-01 (changing this comment will re-build image)
   
  -# Note: updating past stretch (Debian 9) will bump Java past version 8,
  -# which will break the Android SDK.
  -FROM debian:stretch
  +FROM debian:bullseye
   MAINTAINER Flutter Developers <flutter-dev@googlegroups.com>
   
  -RUN apt-get update -y
  -RUN apt-get upgrade -y
  +RUN apt-get update -y && \
  +  apt-get upgrade -y
   
   # Install basics
   RUN apt-get install -y --no-install-recommends \
  
positive.code:     gcloud config set core/disable_usage_reporting true && \
      gcloud config set component_manager/disable_update_check true
  
  # Add nodejs repository to apt sources and install it.
  ENV NODEJS_INSTALL="/opt/nodejs_install"
  RUN mkdir -p "${NODEJS_INSTALL}"
  RUN wget -q https://deb.nodesource.com/setup_10.x -O "${NODEJS_INSTALL}/nodejs_install.sh"
  RUN bash "${NODEJS_INSTALL}/nodejs_install.sh"
  
  # Install the rest of the dependencies.
  RUN apt-get install -y --no-install-recommends \
    locales \
    gcc \
    ruby \
    ruby-dev \
    nodejs \
    lib32stdc++6 \
    libstdc++6 \
    libglu1-mesa \
    build-essential \
    default-jdk-headless \
    google-chrome-stable
  
  # Install the Android SDK Dependency.
  ENV ANDROID_SDK_URL="https://dl.google.com/android/repository/sdk-tools-linux-4333796.zip"
  
negative.code: 
  # Add repo for chrome stable
  RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
  RUN echo 'deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main' | \
      tee /etc/apt/sources.list.d/google-chrome.list
  
  # Add repo for gcloud sdk and install it
  RUN echo "deb [signed-by=/usr/share/keyrings/cloud.google.gpg] https://packages.cloud.google.com/apt cloud-sdk main" | \
  