diff --git a/Controller/Controller.php b/Controller/Controller.php
index 9e0b32a..47e63c4 100644
--- a/Controller/Controller.php
+++ b/Controller/Controller.php
@@ -68,7 +68,7 @@ abstract class Controller extends ModuleAbstract implements WebInterface
      * @var string[]
      * @since 1.0.0
      */
-    protected static $providing = [];
+    protected static array $providing = [];
 
     /**
      * Dependencies.
@@ -76,5 +76,5 @@ abstract class Controller extends ModuleAbstract implements WebInterface
      * @var string[]
      * @since 1.0.0
      */
-    protected static $dependencies = [];
+    protected static array $dependencies = [];
 }
diff --git a/Models/AccountMapper.php b/Models/AccountMapper.php
index f66ab54..c634d86 100644
--- a/Models/AccountMapper.php
+++ b/Models/AccountMapper.php
@@ -35,7 +35,7 @@ final class AccountMapper extends DataMapperAbstract
      * @var array<string, array<string, bool|string|array>>
      * @since 1.0.0
      */
-    protected static $columns = [
+    protected static array $columns = [
         'account_id'         => ['name' => 'account_id',         'type' => 'int',      'internal' => 'id',    'autocomplete' => true],
         'account_status'     => ['name' => 'account_status',     'type' => 'int',      'internal' => 'status'],
         'account_type'       => ['name' => 'account_type',       'type' => 'int',      'internal' => 'type'],
@@ -61,7 +61,7 @@ final class AccountMapper extends DataMapperAbstract
      * @var array<string, array<string, null|string>>
      * @since 1.0.0
      */
-    protected static $hasMany = [
+    protected static array $hasMany = [
         'groups' => [
             'mapper' => GroupMapper::class,
             'table'  => 'account_group',
@@ -76,7 +76,7 @@ final class AccountMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $table = 'account';
+    protected static string $table = 'account';
 
     /**
      * Primary field name.
@@ -84,7 +84,7 @@ final class AccountMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $primaryField = 'account_id';
+    protected static string $primaryField = 'account_id';
 
     /**
      * Created at column
@@ -92,7 +92,7 @@ final class AccountMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $createdAt = 'account_created_at';
+    protected static string $createdAt = 'account_created_at';
 
     /**
      * Get account with permissions
diff --git a/Models/AccountPermissionMapper.php b/Models/AccountPermissionMapper.php
index a459f74..0d610d2 100644
--- a/Models/AccountPermissionMapper.php
+++ b/Models/AccountPermissionMapper.php
@@ -33,7 +33,7 @@ final class AccountPermissionMapper extends DataMapperAbstract
      * @var array<string, array<string, bool|string>>
      * @since 1.0.0
      */
-    protected static $columns = [
+    protected static array $columns = [
         'account_permission_id'         => ['name' => 'account_permission_id', 'type' => 'int', 'internal' => 'id'],
         'account_permission_account'    => ['name' => 'account_permission_account', 'type' => 'int', 'internal' => 'account'],
         'account_permission_unit'       => ['name' => 'account_permission_unit', 'type' => 'int', 'internal' => 'unit'],
@@ -52,7 +52,7 @@ final class AccountPermissionMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $table = 'account_permission';
+    protected static string $table = 'account_permission';
 
     /**
      * Primary field name.
@@ -60,5 +60,5 @@ final class AccountPermissionMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $primaryField = 'account_permission_id';
+    protected static string $primaryField = 'account_permission_id';
 }
diff --git a/Models/Group.php b/Models/Group.php
index 567913e..b760a4d 100644
--- a/Models/Group.php
+++ b/Models/Group.php
@@ -27,7 +27,7 @@ class Group extends \phpOMS\Account\Group
     /**
      * Created at.
      *
-     * @var \DateTime
+     * @var null|\DateTime
      * @since 1.0.0
      */
     protected $createdAt = null;
diff --git a/Models/GroupMapper.php b/Models/GroupMapper.php
index b708afb..b69fc8f 100644
--- a/Models/GroupMapper.php
+++ b/Models/GroupMapper.php
@@ -33,7 +33,7 @@ final class GroupMapper extends DataMapperAbstract
      * @var array<string, array<string, bool|string>>
      * @since 1.0.0
      */
-    protected static $columns = [
+    protected static array $columns = [
         'group_id'       => ['name' => 'group_id', 'type' => 'int', 'internal' => 'id'],
         'group_name'     => ['name' => 'group_name', 'type' => 'string', 'internal' => 'name', 'autocomplete' => true],
         'group_status'   => ['name' => 'group_status', 'type' => 'int', 'internal' => 'status'],
@@ -48,7 +48,7 @@ final class GroupMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $table = 'group';
+    protected static string $table = 'group';
 
     /**
      * Primary field name.
@@ -56,7 +56,7 @@ final class GroupMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $primaryField = 'group_id';
+    protected static string $primaryField = 'group_id';
 
     /**
      * Created at column
@@ -64,7 +64,7 @@ final class GroupMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $createdAt = 'group_created';
+    protected static string $createdAt = 'group_created';
 
     /**
      * Has many relation.
@@ -77,7 +77,7 @@ final class GroupMapper extends DataMapperAbstract
      * @var array<string, array<string, null|string>>
      * @since 1.0.0
      */
-    protected static $hasMany = [
+    protected static array $hasMany = [
         'accounts' => [
             'mapper' => AccountMapper::class,
             'table'  => 'account_group',
diff --git a/Models/GroupPermissionMapper.php b/Models/GroupPermissionMapper.php
index c0ff03b..e335ae1 100644
--- a/Models/GroupPermissionMapper.php
+++ b/Models/GroupPermissionMapper.php
@@ -33,7 +33,7 @@ final class GroupPermissionMapper extends DataMapperAbstract
      * @var array<string, array<string, bool|string>>
      * @since 1.0.0
      */
-    protected static $columns = [
+    protected static array $columns = [
         'group_permission_id'         => ['name' => 'group_permission_id', 'type' => 'int', 'internal' => 'id'],
         'group_permission_group'      => ['name' => 'group_permission_group', 'type' => 'int', 'internal' => 'group'],
         'group_permission_unit'       => ['name' => 'group_permission_unit', 'type' => 'int', 'internal' => 'unit'],
@@ -52,7 +52,7 @@ final class GroupPermissionMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $table = 'group_permission';
+    protected static string $table = 'group_permission';
 
     /**
      * Primary field name.
@@ -60,5 +60,5 @@ final class GroupPermissionMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $primaryField = 'group_permission_id';
+    protected static string $primaryField = 'group_permission_id';
 }
diff --git a/Models/Module.php b/Models/Module.php
index 10ed0a4..c985c75 100644
--- a/Models/Module.php
+++ b/Models/Module.php
@@ -62,7 +62,7 @@ class Module
     /**
      * Created at.
      *
-     * @var \DateTime
+     * @var null|\DateTime
      * @since 1.0.0
      */
     protected $createdAt = null;
diff --git a/Models/ModuleMapper.php b/Models/ModuleMapper.php
index 8b2a13d..86cd5cc 100644
--- a/Models/ModuleMapper.php
+++ b/Models/ModuleMapper.php
@@ -33,7 +33,7 @@ final class ModuleMapper extends DataMapperAbstract
      * @var array<string, array<string, bool|string>>
      * @since 1.0.0
      */
-    protected static $columns = [
+    protected static array $columns = [
         'module_id'     => ['name' => 'module_id', 'type' => 'string', 'internal' => 'id'],
         'module_active' => ['name' => 'module_active', 'type' => 'int', 'internal' => 'status'],
     ];
@@ -44,7 +44,7 @@ final class ModuleMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $table = 'module';
+    protected static string $table = 'module';
 
     /**
      * Primary field name.
@@ -52,5 +52,5 @@ final class ModuleMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $primaryField = 'module_id';
+    protected static string $primaryField = 'module_id';
 }