diff --git a/wp-includes/script-loader.php b/wp-includes/script-loader.php
index 883eadd0e5..ea7f5f4ef7 100644
--- a/wp-includes/script-loader.php
+++ b/wp-includes/script-loader.php
@@ -537,6 +537,7 @@ function wp_default_scripts( &$scripts ) {
 				'updatingMsg'       => __( 'Updating... please wait.' ),
 				'updatedMsg'        => __( 'Update completed successfully.' ),
 				'updateCancel'      => __( 'Update canceled.' ),
+				'beforeunload'      => __( 'Plugin updates may not complete if you navigate away from this page.' ),
 			)
 		) );
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index c263b882af..bcacd678ca 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-beta3-31988';
+$wp_version = '4.2-beta3-31989';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.