public function buildForm(array $form, FormStateInterface $form_state) {
    $config = $this->config('openy_upgrade_tool.settings');
    // TODO: Remove this in Open Y 3.0 release.
    $form['force_mode'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Force mode'),
      '#default_value' => $config->get('force_mode'),
      '#description' => $this->t('In force mode Open Y updates can override any customisation on site.'),
    ];

    $form['actions'] = [
      '#type' => 'actions',
    ];

    $form['actions']['submit'] = [
      '#type' => 'submit',
      '#value' => $this->t('Save'),
      '#button_type' => 'primary',
    ];

    return $form;
  }