diff --git a/core/modules/update/update.install b/core/modules/update/update.install
index 2f87c50..e810129 100644
--- a/core/modules/update/update.install
+++ b/core/modules/update/update.install
@@ -158,7 +158,8 @@ function _update_requirement_check($project, $type) {
  * Rebuild the router to ensure admin/reports/updates/check has CSRF protection.
  */
 function update_update_8001() {
-  \Drupal::service('router.builder')->rebuild();
+  // Empty update forces a call to drupal_flush_all_caches() which rebuilds the
+  // router.
 }
 
 /**