diff --git a/Controller/Controller.php b/Controller/Controller.php
index e588bf4..3c8c1aa 100644
--- a/Controller/Controller.php
+++ b/Controller/Controller.php
@@ -66,7 +66,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string[]
      * @since 1.0.0
      */
-    protected static $providing = [];
+    protected static array $providing = [];
 
     /**
      * Dependencies.
@@ -74,5 +74,5 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string[]
      * @since 1.0.0
      */
-    protected static $dependencies = [];
+    protected static array $dependencies = [];
 }
diff --git a/Models/Arrival.php b/Models/Arrival.php
index 7868ecc..4c183cf 100644
--- a/Models/Arrival.php
+++ b/Models/Arrival.php
@@ -60,7 +60,7 @@ class Arrival
     /**
      * Date of arrival.
      *
-     * @var \DateTime
+     * @var null|\DateTime
      * @since 1.0.0
      */
     private $date = null;
diff --git a/Models/Article.php b/Models/Article.php
index 035af45..4f10ce5 100644
--- a/Models/Article.php
+++ b/Models/Article.php
@@ -112,7 +112,7 @@ class Article
     /**
      * Created.
      *
-     * @var \DateTime
+     * @var null|\DateTime
      * @since 1.0.0
      */
     private $created = null;
diff --git a/Models/Shipping.php b/Models/Shipping.php
index 73dbc9e..af6b624 100644
--- a/Models/Shipping.php
+++ b/Models/Shipping.php
@@ -60,7 +60,7 @@ class Shipping
     /**
      * Date of arrival.
      *
-     * @var \DateTime
+     * @var null|\DateTime
      * @since 1.0.0
      */
     private $delivered = null;