diff --git a/wp-includes/compat.php b/wp-includes/compat.php
index d46b0e5230..596da97707 100644
--- a/wp-includes/compat.php
+++ b/wp-includes/compat.php
@@ -512,7 +512,11 @@ if ( ! function_exists( 'is_countable' ) ) {
 	 * @return bool True if `$var` is countable, false otherwise.
 	 */
 	function is_countable( $var ) {
-		return ( is_array( $var ) || $var instanceof Countable );
+		return ( is_array( $var )
+			|| $var instanceof Countable
+			|| $var instanceof SimpleXMLElement
+			|| $var instanceof ResourceBundle
+		);
 	}
 }
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index d4605f7107..0dd94804dd 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9.6-beta1-43219';
+$wp_version = '4.9.6-beta1-43221';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.