diff --git b/core/modules/comment/comment.module a/core/modules/comment/comment.module
index 796f09f..73bc3db 100644
--- b/core/modules/comment/comment.module
+++ a/core/modules/comment/comment.module
@@ -1243,7 +1243,7 @@ function comment_load($cid, $reset = FALSE) {
  *   to node).
  *
  * @return int|FALSE
- *   The number of new comments or FALSE if the user is not logged in.
+ *   The number of new comments or FALSE if the user is not authenticated.
  */
 function comment_num_new($entity_id, $entity_type, $field_name = NULL, $timestamp = 0) {
   return \Drupal::service('comment.manager')->getCountNewComments($entity_type, $entity_id, $field_name, $timestamp);
diff --git b/core/modules/comment/lib/Drupal/comment/CommentManager.php a/core/modules/comment/lib/Drupal/comment/CommentManager.php
index f6cd26f..136bb5c 100644
--- b/core/modules/comment/lib/Drupal/comment/CommentManager.php
+++ a/core/modules/comment/lib/Drupal/comment/CommentManager.php
@@ -8,11 +8,11 @@
 namespace Drupal\comment;
 
 use Drupal\Component\Utility\String;
-use Drupal\field\FieldInfo;
+use Drupal\Core\Database\Connection;
 use Drupal\Core\Entity\EntityManager;
 use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\Core\Database\Connection;
 use Drupal\Core\Session\AccountInterface;
+use Drupal\field\FieldInfo;
 
 /**
  * Comment manager contains common functions to manage comment fields.
@@ -54,6 +54,10 @@ class CommentManager implements CommentManagerInterface {
    *   The field info service.
    * @param \Drupal\Core\Entity\EntityManager $entity_manager
    *   The entity manager service.
+   * @param \Drupal\Core\Database\Connection $connection
+   *   The database connection.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler.
    */
   public function __construct(FieldInfo $field_info, EntityManager $entity_manager, Connection $connection, ModuleHandlerInterface $module_handler) {
     $this->fieldInfo = $field_info;
@@ -219,28 +223,29 @@ public function getFieldUIPageTitle($field_name) {
   }
 
   /**
-   * Returns the number of new comments for an user and the specified entity.
+   * Returns the number of new comments available on a given entity for a user.
    *
    * @param string $entity_type
    *   Entity type of the entity to which the comments are attached.
    * @param int $entity_id
    *   Entity ID of the entity to which the comments are attached.
    * @param string $field_name
-   *   (optional) The field_name to count comments for. Defaults to NULL.
+   *   The field_name to count comments for. Defaults to any field.
    * @param int $timestamp
-   *   Time to count from (defaults to time of last user access to node).
+   *   Time to count from. Defaults to time of last user access to node.
    * @param \Drupal\Core\Session\AccountInterface $account
-   *   The user for which to count the new comments. Defaults to NULL.
+   *   The user for which to count the new comments. Defaults to the current
+   *   user.
    *
    * @return int|FALSE
-   *   The number of new comments or FALSE if the user is not logged in.
+   *   The number of new comments or FALSE if the user is not authenticated.
    */
   public function getCountNewComments($entity_type, $entity_id, $field_name = NULL, $timestamp = 0, AccountInterface $account = NULL) {
     if (!isset($account)) {
       $account = \Drupal::currentUser();
     }
     if ($account->isAuthenticated() && $this->moduleHandler->moduleExists('history')) {
-      // Retrieve the timestamp when the current user last viewed this entity.
+      // Retrieve the timestamp when the user last viewed this entity.
       if (!$timestamp) {
         if ($entity_type == 'node') {
           $timestamp = history_read($entity_id);
@@ -257,7 +262,7 @@ public function getCountNewComments($entity_type, $entity_id, $field_name = NULL
           }
         }
       }
-      $timestamp = ($timestamp > HISTORY_READ_LIMIT ? $timestamp : HISTORY_READ_LIMIT);
+      $timestamp = $timestamp > HISTORY_READ_LIMIT ? $timestamp : HISTORY_READ_LIMIT;
 
       // Use the timestamp to retrieve the number of new comments.
       $query = $this->connection->select('comment', 'c');
@@ -274,9 +279,7 @@ public function getCountNewComments($entity_type, $entity_id, $field_name = NULL
       return $query->execute()
         ->fetchField();
     }
-    else {
-      return FALSE;
-    }
+    return FALSE;
   }
 
 }