post_install() {
  cat <<'MESSAGE'
==> This is the new melody-agent: it plays for the new C++ melodyd only.

It no longer uses mpv, melody-agent.toml or the old MPD port. Without
--server it finds the engines on the network by itself and plays for them;
options go in ~/.config/melody/agent.conf for the user service:

  echo 'MELODY_AGENT_OPTIONS=' > ~/.config/melody/agent.conf
  systemctl --user enable --now melody-agent.service

A machine that runs melodyd does not need it: start that engine with
--agent instead.
MESSAGE
}

post_upgrade() {
  # Coming from the Go agent (r116 and before), say what changed.
  if [ "$(vercmp "$2" r300)" -lt 0 ]; then
    post_install
  fi
}
