/**
  * Sets the recipient mode of the API call to either `single` or `all` based on the audience we want to send the
  * push notification to.
  *
  * Note: if the recipient mode is set to `single`, we require a device token to be set with `set_device_token`.
  *
  * @param string $mode
  * @return bool
  */
 public static function set_recipient_mode($mode = 'all')
 {
     if ($mode !== 'all' && $mode !== 'single') {
         return false;
     }
     self::$_recipient_mode = $mode;
     return true;
 }
<?php

/**
 * Plugin Name: PushUp Notifications
 * Plugin URI:  http://pushupnotifications.com
 * Description: Desktop push notifications for your WordPress powered website, starting with OS X Mavericks.
 * Version:     1.2.2
 * Author:      10up
 * Author URI:  http://10up.com
 * License:     GPLv2 or later
 */
// Exit if accessed directly
if (!defined('ABSPATH')) {
    exit;
}
// Include classes
require_once plugin_dir_path(__FILE__) . 'includes/class-core.php';
require_once plugin_dir_path(__FILE__) . 'includes/class-json-api.php';
require_once plugin_dir_path(__FILE__) . 'includes/class-authentication.php';
require_once plugin_dir_path(__FILE__) . 'includes/class-push-notifications.php';
// Instantiate objects
PushUp_Notifications_Core::instance();
PushUp_Notifications_JSON_API::instance();
PushUp_Notifications_Authentication::instance();
PushUp_Notifications::instance();