diff --git a/Admin/Install/Navigation.php b/Admin/Install/Navigation.php
index e655cc5..0da5615 100644
--- a/Admin/Install/Navigation.php
+++ b/Admin/Install/Navigation.php
@@ -36,7 +36,7 @@ class Navigation
      *
      * @since  1.0.0
      */
-    public static function install(string $path = null, DatabasePool $dbPool = null) : void
+    public static function install(string $path, DatabasePool $dbPool) : void
     {
         \Modules\Navigation\Admin\Installer::installExternal($dbPool, ['path' => __DIR__ . '/Navigation.install.json']);
     }
diff --git a/Controller/BackendController.php b/Controller/BackendController.php
index 90fd432..4fc5ab7 100644
--- a/Controller/BackendController.php
+++ b/Controller/BackendController.php
@@ -17,6 +17,7 @@ namespace Modules\Calendar\Controller;
 use Modules\Calendar\Models\CalendarMapper;
 
 use phpOMS\Asset\AssetType;
+use phpOMS\Contract\RenderableInterface;
 use phpOMS\Message\RequestAbstract;
 use phpOMS\Message\ResponseAbstract;
 use phpOMS\Stdlib\Base\SmartDateTime;
@@ -37,16 +38,16 @@ final class BackendController extends Controller
      * @param ResponseAbstract $response Response
      * @param mixed            $data     Generic data
      *
-     * @return \Serializable
+     * @return RenderableInterface
      *
      * @since  1.0.0
      * @codeCoverageIgnore
      */
-    public function viewCalendarDashboard(RequestAbstract $request, ResponseAbstract $response, $data = null) : \Serializable
+    public function viewCalendarDashboard(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
     {
         $view = new View($this->app, $request, $response);
 
-        /** @var Head $head */
+        /** @var \phpOMS\Model\Html\Head $head */
         $head = $response->get('Content')->getData('head');
         $head->addAsset(AssetType::CSS, '/Modules/Calendar/Theme/Backend/css/styles.css');
 
@@ -68,14 +69,14 @@ final class BackendController extends Controller
      * @param ResponseAbstract $response Response
      * @param mixed            $data     Generic data
      *
-     * @return \Serializable
+     * @return RenderableInterface
      *
      * @since  1.0.0
      * @codeCoverageIgnore
      */
-    public function viewDashboard(RequestAbstract $request, ResponseAbstract $response, $data = null) : \Serializable
+    public function viewDashboard(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
     {
-        /** @var Head $head */
+        /** @var \phpOMS\Model\Html\Head $head */
         $head = $response->get('Content')->getData('head');
         $head->addAsset(AssetType::CSS, '/Modules/Calendar/Theme/Backend/css/styles.css');
 
diff --git a/Controller/Controller.php b/Controller/Controller.php
index 522e611..4340397 100644
--- a/Controller/Controller.php
+++ b/Controller/Controller.php
@@ -14,7 +14,6 @@ declare(strict_types=1);
 
 namespace Modules\Calendar\Controller;
 
-
 use phpOMS\Module\ModuleAbstract;
 use phpOMS\Module\WebInterface;
 
diff --git a/Models/Calendar.php b/Models/Calendar.php
index d313f91..05e5133 100644
--- a/Models/Calendar.php
+++ b/Models/Calendar.php
@@ -54,7 +54,7 @@ class Calendar
     /**
      * Created at.
      *
-     * @var \Datetime
+     * @var \DateTime
      * @since 1.0.0
      */
     private $createdAt = null;
@@ -62,7 +62,7 @@ class Calendar
     /**
      * Current date of the calendar.
      *
-     * @var \Datetime
+     * @var \DateTime
      * @since 1.0.0
      */
     private $date = null;
diff --git a/Models/CalendarMapper.php b/Models/CalendarMapper.php
index 5f53cc6..0a2f553 100644
--- a/Models/CalendarMapper.php
+++ b/Models/CalendarMapper.php
@@ -53,11 +53,6 @@ final class CalendarMapper extends DataMapperAbstract
      *
      * @var array<string, array<string, null|string>>
      * @since 1.0.0
-     */    /**
-     * Has many relation.
-     *
-     * @var array<string, array<string, string>>
-     * @since 1.0.0
      */
     protected static $hasMany = [
         'events' => [
diff --git a/Models/Event.php b/Models/Event.php
index ba2dcca..ece9595 100644
--- a/Models/Event.php
+++ b/Models/Event.php
@@ -56,7 +56,7 @@ class Event
     /**
      * Created.
      *
-     * @var \Datetime
+     * @var \DateTime
      * @since 1.0.0
      */
     private $createdAt = null;
@@ -178,19 +178,13 @@ class Event
     /**
      * @param Account $person Person to add
      *
-     * @return int Account id/position
+     * @return void
      *
      * @since  1.0.0
      */
-    public function addPerson(Account $person)
+    public function addPerson(Account $person) : void
     {
-        $this->people[] = $person;
-
-        \end($this->people);
-        $key = \key($this->people);
-        \reset($this->people);
-
-        return $key;
+        $this->people[$person->getId()] = $person;
     }
 
     /**