post_upgrade() {
  # Executed only when upgrading from 0.x.x to xxxx.xx.xx
  if [[ "${2:0:1}" == "0" ]]; then
    cat <<EOF

Next time you launch Google Calendar you'll need to log in again. If you'd like to avoid that, run "mv ~/.config/google-calendar-nativefier-e22938 ~/.config/googlecalendar-nativefier-e22938" (note the missing hyphen).

EOF
  fi
}