diff --git a/wp-includes/class-wp-ajax-response.php b/wp-includes/class-wp-ajax-response.php
index 0a8016c980..b32f7aa535 100644
--- a/wp-includes/class-wp-ajax-response.php
+++ b/wp-includes/class-wp-ajax-response.php
@@ -13,7 +13,7 @@ class WP_Ajax_Response {
 	 * @var array
 	 * @access private
 	 */
-	var $responses = array();
+	private $responses = array();
 
 	/**
 	 * Constructor - Passes args to {@link WP_Ajax_Response::add()}.
@@ -24,11 +24,22 @@ class WP_Ajax_Response {
 	 * @param string|array $args Optional. Will be passed to add() method.
 	 * @return WP_Ajax_Response
 	 */
-	function __construct( $args = '' ) {
+	public function __construct( $args = '' ) {
 		if ( !empty($args) )
 			$this->add($args);
 	}
 
+	/**
+	 * Make private properties readable for backwards compatibility
+	 *
+	 * @since 4.0.0
+	 * @param string $name
+	 * @return mixed
+	 */
+	public function __get( $name ) {
+		return $this->$name;
+	}
+
 	/**
 	 * Append to XML response based on given arguments.
 	 *
@@ -52,7 +63,7 @@ class WP_Ajax_Response {
 	 * @param string|array $args Override defaults.
 	 * @return string XML response.
 	 */
-	function add( $args = '' ) {
+	public function add( $args = '' ) {
 		$defaults = array(
 			'what' => 'object', 'action' => false,
 			'id' => '0', 'old_id' => false,
@@ -133,7 +144,7 @@ class WP_Ajax_Response {
 	 *
 	 * @since 2.1.0
 	 */
-	function send() {
+	public function send() {
 		header( 'Content-Type: text/xml; charset=' . get_option( 'blog_charset' ) );
 		echo "<?xml version='1.0' encoding='" . get_option( 'blog_charset' ) . "' standalone='yes'?><wp_ajax>";
 		foreach ( (array) $this->responses as $response )