diff --git a/Models/RelationAbstract.php b/Models/RelationAbstract.php
index 75846b3..bf48d15 100644
--- a/Models/RelationAbstract.php
+++ b/Models/RelationAbstract.php
@@ -33,7 +33,7 @@ abstract class RelationAbstract implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $id = 0;
+    protected int $id = 0;
 
     /**
      * Duty.
@@ -41,7 +41,7 @@ abstract class RelationAbstract implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $duty = DutyType::TO;
+    protected int $duty = DutyType::TO;
 
 
     /**
@@ -50,7 +50,7 @@ abstract class RelationAbstract implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $element = 0;
+    protected int $element = 0;
 
     /**
      * Get id.
diff --git a/Models/Task.php b/Models/Task.php
index ec36a98..e4b6dee 100644
--- a/Models/Task.php
+++ b/Models/Task.php
@@ -36,7 +36,7 @@ class Task implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $id = 0;
+    protected int $id = 0;
 
     /**
      * Title.
@@ -44,7 +44,7 @@ class Task implements \JsonSerializable
      * @var string
      * @since 1.0.0
      */
-    protected $title = '';
+    protected string $title = '';
 
     /**
      * Creator.
@@ -60,7 +60,7 @@ class Task implements \JsonSerializable
      * @var null|\DateTime
      * @since 1.0.0
      */
-    protected $createdAt = null;
+    protected ?\DateTime $createdAt = null;
 
     /**
      * Description.
@@ -68,7 +68,7 @@ class Task implements \JsonSerializable
      * @var string
      * @since 1.0.0
      */
-    protected $description = '';
+    protected string $description = '';
 
     /**
      * Description raw.
@@ -76,7 +76,7 @@ class Task implements \JsonSerializable
      * @var string
      * @since 1.0.0
      */
-    protected $descriptionRaw = '';
+    protected string $descriptionRaw = '';
 
     /**
      * Type.
@@ -84,7 +84,7 @@ class Task implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $type = TaskType::SINGLE;
+    protected int $type = TaskType::SINGLE;
 
     /**
      * Status.
@@ -92,7 +92,7 @@ class Task implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $status = TaskStatus::OPEN;
+    protected int $status = TaskStatus::OPEN;
 
     /**
      * Task can be closed by user.
@@ -100,7 +100,7 @@ class Task implements \JsonSerializable
      * @var bool
      * @since 1.0.0
      */
-    protected $isClosable = true;
+    protected bool $isClosable = true;
 
     /**
      * Task can be edited by user.
@@ -108,7 +108,7 @@ class Task implements \JsonSerializable
      * @var bool
      * @since 1.0.0
      */
-    protected $isEditable = true;
+    protected bool $isEditable = true;
 
     /**
      * Start.
@@ -140,7 +140,7 @@ class Task implements \JsonSerializable
      * @var TaskElement[]
      * @since 1.0.0
      */
-    protected $taskElements = [];
+    protected array $taskElements = [];
 
     /**
      * Task elements.
@@ -148,7 +148,7 @@ class Task implements \JsonSerializable
      * @var Tag[]
      * @since 1.0.0
      */
-    protected $tags = [];
+    protected array $tags = [];
 
     /**
      * Schedule
@@ -164,7 +164,7 @@ class Task implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $priority = TaskPriority::NONE;
+    protected int $priority = TaskPriority::NONE;
 
     /**
      * Media files
@@ -172,7 +172,7 @@ class Task implements \JsonSerializable
      * @var array
      * @since 1.0.0
      */
-    protected $media = [];
+    protected array $media = [];
 
     /**
      * Constructor.
diff --git a/Models/TaskElement.php b/Models/TaskElement.php
index a862f98..c0a8549 100644
--- a/Models/TaskElement.php
+++ b/Models/TaskElement.php
@@ -36,7 +36,7 @@ class TaskElement implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    private $id = 0;
+    private int $id = 0;
 
     /**
      * Description.
@@ -44,7 +44,7 @@ class TaskElement implements \JsonSerializable
      * @var string
      * @since 1.0.0
      */
-    private $description = '';
+    private string $description = '';
 
     /**
      * Description raw.
@@ -52,7 +52,7 @@ class TaskElement implements \JsonSerializable
      * @var string
      * @since 1.0.0
      */
-    private $descriptionRaw = '';
+    private string $descriptionRaw = '';
 
     /**
      * Task.
@@ -60,7 +60,7 @@ class TaskElement implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    private $task = 0;
+    private int $task = 0;
 
     /**
      * Creator.
@@ -76,7 +76,7 @@ class TaskElement implements \JsonSerializable
      * @var null|\DateTime
      * @since 1.0.0
      */
-    private $createdAt = null;
+    private ?\DateTime $createdAt = null;
 
     /**
      * Status.
@@ -84,7 +84,7 @@ class TaskElement implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    private $status = TaskStatus::OPEN;
+    private int $status = TaskStatus::OPEN;
 
     /**
      * Due.
@@ -92,7 +92,7 @@ class TaskElement implements \JsonSerializable
      * @var null|\DateTime
      * @since 1.0.0
      */
-    private $due = null;
+    private ?\DateTime $due = null;
 
     /**
      * Priority
@@ -100,7 +100,7 @@ class TaskElement implements \JsonSerializable
      * @var int
      * @since 1.0.0
      */
-    protected $priority = TaskPriority::NONE;
+    protected int $priority = TaskPriority::NONE;
 
     /**
      * Media.
@@ -108,7 +108,7 @@ class TaskElement implements \JsonSerializable
      * @var array
      * @since 1.0.0
      */
-    private $media = [];
+    private array $media = [];
 
     /**
      * Accounts who received this task element.
@@ -116,7 +116,7 @@ class TaskElement implements \JsonSerializable
      * @var array
      * @since 1.0.0
      */
-    protected $accRelation = [];
+    protected array $accRelation = [];
 
     /**
      * Groups who received this task element.
@@ -124,7 +124,7 @@ class TaskElement implements \JsonSerializable
      * @var array
      * @since 1.0.0
      */
-    protected $grpRelation = [];
+    protected array $grpRelation = [];
 
     /**
      * Constructor.
diff --git a/Models/TaskTemplate.php b/Models/TaskTemplate.php
index a0d676b..956b0d0 100644
--- a/Models/TaskTemplate.php
+++ b/Models/TaskTemplate.php
@@ -30,5 +30,5 @@ class TaskTemplate extends Task
      * @var int
      * @since 1.0.0
      */
-    protected $type = TaskType::TEMPLATE;
+    protected int $type = TaskType::TEMPLATE;
 }