diff --git a/Controller/Controller.php b/Controller/Controller.php
index 8f006ad..59e0a14 100644
--- a/Controller/Controller.php
+++ b/Controller/Controller.php
@@ -74,7 +74,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string[]
      * @since 1.0.0
      */
-    protected static $providing = [];
+    protected static array $providing = [];
 
     /**
      * Dependencies.
@@ -82,5 +82,5 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string[]
      * @since 1.0.0
      */
-    protected static $dependencies = [];
+    protected static array $dependencies = [];
 }
diff --git a/Models/Report.php b/Models/Report.php
index 76392e2..a300f80 100644
--- a/Models/Report.php
+++ b/Models/Report.php
@@ -68,7 +68,7 @@ class Report implements \JsonSerializable
     /**
      * Report created at.
      *
-     * @var \DateTime
+     * @var null|\DateTime
      * @since 1.0.0
      */
     protected $createdAt = null;
diff --git a/Models/ReportMapper.php b/Models/ReportMapper.php
index 81a33fb..7c22784 100644
--- a/Models/ReportMapper.php
+++ b/Models/ReportMapper.php
@@ -26,7 +26,7 @@ final class ReportMapper extends DataMapperAbstract
      * @var array<string, array<string, bool|string>>
      * @since 1.0.0
      */
-    protected static $columns = [
+    protected static array $columns = [
         'helper_report_id'       => ['name' => 'helper_report_id', 'type' => 'int', 'internal' => 'id'],
         'helper_report_status'   => ['name' => 'helper_report_status', 'type' => 'int', 'internal' => 'status'],
         'helper_report_title'    => ['name' => 'helper_report_title', 'type' => 'string', 'internal' => 'title'],
@@ -44,7 +44,7 @@ final class ReportMapper extends DataMapperAbstract
      * @var array<string, array<string, string>>
      * @since 1.0.0
      */
-    protected static $ownsOne = [
+    protected static array $ownsOne = [
         'source'   => [
             'mapper' => \Modules\Media\Models\CollectionMapper::class,
             'src'    => 'helper_report_media',
@@ -61,7 +61,7 @@ final class ReportMapper extends DataMapperAbstract
      * @var array<string, array<string, string>>
      * @since 1.0.0
      */
-    protected static $belongsTo = [
+    protected static array $belongsTo = [
         'createdBy' => [
             'mapper' => AccountMapper::class,
             'src'    => 'helper_report_creator',
@@ -74,7 +74,7 @@ final class ReportMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $table = 'helper_report';
+    protected static string $table = 'helper_report';
 
     /**
      * Primary field name.
@@ -82,7 +82,7 @@ final class ReportMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $primaryField = 'helper_report_id';
+    protected static string $primaryField = 'helper_report_id';
 
     /**
      * Created at.
@@ -90,5 +90,5 @@ final class ReportMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $createdAt = 'helper_report_created';
+    protected static string $createdAt = 'helper_report_created';
 }
diff --git a/Models/Template.php b/Models/Template.php
index f01ee15..89d9594 100644
--- a/Models/Template.php
+++ b/Models/Template.php
@@ -84,7 +84,7 @@ class Template implements \JsonSerializable
     /**
      * Template created at.
      *
-     * @var \DateTime
+     * @var null|\DateTime
      * @since 1.0.0
      */
     protected $createdAt = null;
diff --git a/Models/TemplateMapper.php b/Models/TemplateMapper.php
index d94d3aa..7a7fdd8 100644
--- a/Models/TemplateMapper.php
+++ b/Models/TemplateMapper.php
@@ -27,7 +27,7 @@ final class TemplateMapper extends DataMapperAbstract
      * @var array<string, array<string, bool|string>>
      * @since 1.0.0
      */
-    protected static $columns = [
+    protected static array $columns = [
         'helper_template_id'         => ['name' => 'helper_template_id', 'type' => 'int', 'internal' => 'id'],
         'helper_template_status'     => ['name' => 'helper_template_status', 'type' => 'int', 'internal' => 'status'],
         'helper_template_title'      => ['name' => 'helper_template_title', 'type' => 'string', 'internal' => 'name'],
@@ -49,7 +49,7 @@ final class TemplateMapper extends DataMapperAbstract
      * @var array<string, array<string, string>>
      * @since 1.0.0
      */
-    protected static $ownsOne = [
+    protected static array $ownsOne = [
         'source' => [
             'mapper' => CollectionMapper::class,
             'src'    => 'helper_template_media',
@@ -62,7 +62,7 @@ final class TemplateMapper extends DataMapperAbstract
      * @var array<string, array<string, string>>
      * @since 1.0.0
      */
-    protected static $belongsTo = [
+    protected static array $belongsTo = [
         'createdBy' => [
             'mapper' => AccountMapper::class,
             'src'    => 'helper_template_creator',
@@ -75,7 +75,7 @@ final class TemplateMapper extends DataMapperAbstract
      * @var array<string, array<string, null|string>>
      * @since 1.0.0
      */
-    protected static $hasMany = [
+    protected static array $hasMany = [
         'reports' => [
             'mapper' => ReportMapper::class,
             'table'  => 'helper_report',
@@ -90,7 +90,7 @@ final class TemplateMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $table = 'helper_template';
+    protected static string $table = 'helper_template';
 
     /**
      * Created at.
@@ -98,7 +98,7 @@ final class TemplateMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $createdAt = 'helper_template_created';
+    protected static string $createdAt = 'helper_template_created';
 
     /**
      * Primary field name.
@@ -106,5 +106,5 @@ final class TemplateMapper extends DataMapperAbstract
      * @var string
      * @since 1.0.0
      */
-    protected static $primaryField = 'helper_template_id';
+    protected static string $primaryField = 'helper_template_id';
 }