diff --git a/comment_notify.module b/comment_notify.module
index d1ada09..bb8e84c 100644
--- a/comment_notify.module
+++ b/comment_notify.module
@@ -352,7 +352,7 @@ function _comment_notify_mailalert(CommentInterface $comment) {
     // Send to a subscribed author if they are not the current commenter.
     if ($entity->hasField($author_field)) {
       // If the entity is a user object, then the user object is the "author'.
-      if ($entity instanceof User) {
+      if ($entity instanceof Drupal\user\Entity\User) {
         $author = $entity;
       }
       // For now assume every other entity has an "owner".