Plugin_Upgrader::upgrade_strings

	 *
	 * @see check_package()
	 */
	public $new_plugin_data = array();

	/**
	 * Initialize the upgrade strings.
	 *
	 * @since 2.8.0
	 */
	public function upgrade_strings() {
		$this->strings['up_to_date'] = __( 'The plugin is at the latest version.' );