diff --git a/Models/NewsArticle.php b/Models/NewsArticle.php
index 106cb0b..52f456b 100755
--- a/Models/NewsArticle.php
+++ b/Models/NewsArticle.php
@@ -93,7 +93,7 @@ class NewsArticle implements \JsonSerializable, ArrayableInterface
      * @var \DateTime
      * @since 1.0.0
      */
-    private \DateTime $createdAt;
+    private \DateTimeImmutable $createdAt;
 
     /**
      * Creator.
@@ -143,7 +143,7 @@ class NewsArticle implements \JsonSerializable, ArrayableInterface
     public function __construct()
     {
         $this->createdBy = new NullAccount();
-        $this->createdAt = new \DateTime('now');
+        $this->createdAt = new \DateTimeImmutable('now');
         $this->publish   = new \DateTime('now');
     }
 
@@ -232,7 +232,7 @@ class NewsArticle implements \JsonSerializable, ArrayableInterface
      *
      * @since 1.0.0
      */
-    public function getCreatedAt() : \DateTime
+    public function getCreatedAt() : \DateTimeInterface
     {
         return $this->createdAt;
     }
diff --git a/Models/NewsArticleMapper.php b/Models/NewsArticleMapper.php
index fca7598..49f7ce6 100755
--- a/Models/NewsArticleMapper.php
+++ b/Models/NewsArticleMapper.php
@@ -51,7 +51,7 @@ final class NewsArticleMapper extends DataMapperAbstract
         'news_type'         => ['name' => 'news_type',       'type' => 'int',      'internal' => 'type'],
         'news_featured'     => ['name' => 'news_featured',   'type' => 'bool',     'internal' => 'featured'],
         'news_comment_list' => ['name' => 'news_comment_list',   'type' => 'int',     'internal' => 'comments'],
-        'news_created_at'   => ['name' => 'news_created_at', 'type' => 'DateTime', 'internal' => 'createdAt', 'readonly' => true],
+        'news_created_at'   => ['name' => 'news_created_at', 'type' => 'DateTimeImmutable', 'internal' => 'createdAt', 'readonly' => true],
         'news_created_by'   => ['name' => 'news_created_by', 'type' => 'int',      'internal' => 'createdBy', 'readonly' => true],
     ];