diff --git a/wp-admin/admin.php b/wp-admin/admin.php
index 1040995f1b..22813cc74f 100644
--- a/wp-admin/admin.php
+++ b/wp-admin/admin.php
@@ -63,7 +63,11 @@ if ( get_option('db_upgraded') ) {
 	 */
 	} elseif ( apply_filters( 'do_mu_upgrade', true ) ) {
 		$c = get_blog_count();
-		// If 50 or fewer sites, run every time. Else, run "about ten percent" of the time. Shh, don't check that math.
+
+		/*
+		 * If there are 50 or fewer sites, run every time. Otherwise, throttle to reduce load:
+		 * attempt to do no more than threshold value, with some +/- allowed.
+		 */
 		if ( $c <= 50 || ( $c > 50 && mt_rand( 0, (int)( $c / 50 ) ) == 1 ) ) {
 			require_once( ABSPATH . WPINC . '/http.php' );
 			$response = wp_remote_get( admin_url( 'upgrade.php?step=1' ), array( 'timeout' => 120, 'httpversion' => '1.1' ) );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index b1834c5d5e..a8aacf381a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31296';
+$wp_version = '4.2-alpha-31297';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.