diff --git a/composer.json b/composer.json
index c658a96..170f9ef 100644
--- a/composer.json
+++ b/composer.json
@@ -59,6 +59,7 @@
         "contao-manager-plugin": "Terminal42\\ChangeLanguage\\ContaoManager\\Plugin"
     },
     "scripts": {
-        "cs-fixer": "@php tools/ecs/vendor/bin/ecs check src/ --config tools/ecs/config.php --fix --ansi"
+        "cs-fixer": "@php tools/ecs/vendor/bin/ecs check src/ --config tools/ecs/config.php --fix --ansi",
+        "rector": "@php tools/rector/vendor/bin/rector --config tools/rector/config.php --ansi"
     }
 }
diff --git a/src/Event/ChangelanguageNavigationEvent.php b/src/Event/ChangelanguageNavigationEvent.php
index 8ccb9ee..0ff676e 100644
--- a/src/Event/ChangelanguageNavigationEvent.php
+++ b/src/Event/ChangelanguageNavigationEvent.php
@@ -9,25 +9,10 @@
 
 class ChangelanguageNavigationEvent
 {
-    /**
-     * @var NavigationItem
-     */
-    private $navigationItem;
-
-    /**
-     * @var UrlParameterBag
-     */
-    private $urlParameterBag;
-
-    /**
-     * @var bool
-     */
-    private $skipped = false;
-
-    /**
-     * @var bool
-     */
-    private $stopPropagation = false;
+    private NavigationItem $navigationItem;
+    private UrlParameterBag $urlParameterBag;
+    private bool $skipped = false;
+    private bool $stopPropagation = false;
 
     public function __construct(NavigationItem $navigationItem, UrlParameterBag $urlParameters)
     {
diff --git a/src/EventListener/BackendView/ArticleViewListener.php b/src/EventListener/BackendView/ArticleViewListener.php
index 23b8f1f..f40f0b8 100644
--- a/src/EventListener/BackendView/ArticleViewListener.php
+++ b/src/EventListener/BackendView/ArticleViewListener.php
@@ -86,9 +86,7 @@ protected function getAvailableLanguages(PageModel $page)
 
             $articles = array_values(array_filter(
                 $articles,
-                function (ArticleModel $article) {
-                    return $article->inColumn === $this->currentArticle->inColumn;
-                }
+                fn (ArticleModel $article) => $article->inColumn === $this->currentArticle->inColumn
             ));
 
             if (1 === \count($articles)) {
diff --git a/src/EventListener/CallbackSetupListener.php b/src/EventListener/CallbackSetupListener.php
index 432ae70..1715754 100644
--- a/src/EventListener/CallbackSetupListener.php
+++ b/src/EventListener/CallbackSetupListener.php
@@ -4,46 +4,53 @@
 
 namespace Terminal42\ChangeLanguage\EventListener;
 
+use Terminal42\ChangeLanguage\EventListener\BackendView\ArticleViewListener;
+use Terminal42\ChangeLanguage\EventListener\BackendView\PageViewListener;
+use Terminal42\ChangeLanguage\EventListener\BackendView\ParentChildViewListener;
+use Terminal42\ChangeLanguage\EventListener\DataContainer\ArticleListener;
+use Terminal42\ChangeLanguage\EventListener\DataContainer\CalendarEventsListener;
+use Terminal42\ChangeLanguage\EventListener\DataContainer\FaqListener;
 use Terminal42\ChangeLanguage\EventListener\DataContainer\MissingLanguageIconListener;
+use Terminal42\ChangeLanguage\EventListener\DataContainer\NewsListener;
+use Terminal42\ChangeLanguage\EventListener\DataContainer\PageInitializationListener;
+use Terminal42\ChangeLanguage\EventListener\DataContainer\PageOperationListener;
+use Terminal42\ChangeLanguage\EventListener\DataContainer\ParentTableListener;
 
 class CallbackSetupListener
 {
-    private static $listeners = [
+    private static array $listeners = [
         'tl_page' => [
-            'Terminal42\ChangeLanguage\EventListener\DataContainer\PageInitializationListener',
-            'Terminal42\ChangeLanguage\EventListener\DataContainer\PageOperationListener',
-            'Terminal42\ChangeLanguage\EventListener\BackendView\PageViewListener',
+            PageInitializationListener::class,
+            PageOperationListener::class,
+            PageViewListener::class,
         ],
         'tl_article' => [
-            'Terminal42\ChangeLanguage\EventListener\DataContainer\ArticleListener',
-            'Terminal42\ChangeLanguage\EventListener\BackendView\PageViewListener',
-            'Terminal42\ChangeLanguage\EventListener\BackendView\ArticleViewListener',
+            ArticleListener::class,
+            PageViewListener::class,
+            ArticleViewListener::class,
         ],
         'tl_content' => [
-            'Terminal42\ChangeLanguage\EventListener\BackendView\ArticleViewListener',
-            'Terminal42\ChangeLanguage\EventListener\BackendView\ParentChildViewListener',
+            ArticleViewListener::class,
+            ParentChildViewListener::class,
         ],
-        'tl_news_archive' => ['Terminal42\ChangeLanguage\EventListener\DataContainer\ParentTableListener'],
-        'tl_calendar' => ['Terminal42\ChangeLanguage\EventListener\DataContainer\ParentTableListener'],
-        'tl_faq_category' => ['Terminal42\ChangeLanguage\EventListener\DataContainer\ParentTableListener'],
+        'tl_news_archive' => [ParentTableListener::class],
+        'tl_calendar' => [ParentTableListener::class],
+        'tl_faq_category' => [ParentTableListener::class],
         'tl_news' => [
-            'Terminal42\ChangeLanguage\EventListener\DataContainer\NewsListener',
-            'Terminal42\ChangeLanguage\EventListener\BackendView\ParentChildViewListener',
+            NewsListener::class,
+            ParentChildViewListener::class,
         ],
         'tl_calendar_events' => [
-            'Terminal42\ChangeLanguage\EventListener\DataContainer\CalendarEventsListener',
-            'Terminal42\ChangeLanguage\EventListener\BackendView\ParentChildViewListener',
+            CalendarEventsListener::class,
+            ParentChildViewListener::class,
         ],
         'tl_faq' => [
-            'Terminal42\ChangeLanguage\EventListener\DataContainer\FaqListener',
-            'Terminal42\ChangeLanguage\EventListener\BackendView\ParentChildViewListener',
+            FaqListener::class,
+            ParentChildViewListener::class,
         ],
     ];
 
-    /**
-     * @var MissingLanguageIconListener
-     */
-    private $labelListener;
+    private MissingLanguageIconListener $labelListener;
 
     /**
      * Constructor.
diff --git a/src/EventListener/DataContainer/LanguageMainTrait.php b/src/EventListener/DataContainer/LanguageMainTrait.php
index deddc32..a715c3f 100644
--- a/src/EventListener/DataContainer/LanguageMainTrait.php
+++ b/src/EventListener/DataContainer/LanguageMainTrait.php
@@ -14,9 +14,7 @@ protected function addLanguageMainField(): void
             'label' => &$GLOBALS['TL_LANG'][$this->getTable()]['languageMain'],
             'exclude' => true,
             'inputType' => 'select',
-            'options_callback' => function (DataContainer $dc) {
-                return $this->onLanguageMainOptions($dc);
-            },
+            'options_callback' => fn (DataContainer $dc) => $this->onLanguageMainOptions($dc),
             'eval' => [
                 'includeBlankOption' => true,
                 'blankOptionLabel' => &$GLOBALS['TL_LANG'][$this->getTable()]['languageMain'][2],
diff --git a/src/EventListener/DataContainer/MissingLanguageIconListener.php b/src/EventListener/DataContainer/MissingLanguageIconListener.php
index 8d36dff..f38866d 100644
--- a/src/EventListener/DataContainer/MissingLanguageIconListener.php
+++ b/src/EventListener/DataContainer/MissingLanguageIconListener.php
@@ -22,7 +22,7 @@
 
 class MissingLanguageIconListener
 {
-    private static $callbacks = [
+    private static array $callbacks = [
         'tl_page' => 'onPageLabel',
         'tl_article' => 'onArticleLabel',
         'tl_news' => 'onNewsChildRecords',
@@ -40,9 +40,7 @@ public function register($table): void
         if (\array_key_exists($table, self::$callbacks)) {
             LabelCallback::createAndRegister(
                 $table,
-                function (array $args, $previousResult) use ($table) {
-                    return $this->{self::$callbacks[$table]}($args, $previousResult);
-                }
+                fn (array $args, $previousResult) => $this->{self::$callbacks[$table]}($args, $previousResult)
             );
         }
     }
diff --git a/src/EventListener/DataContainer/PageOperationListener.php b/src/EventListener/DataContainer/PageOperationListener.php
index 3830106..c218cd4 100644
--- a/src/EventListener/DataContainer/PageOperationListener.php
+++ b/src/EventListener/DataContainer/PageOperationListener.php
@@ -134,11 +134,9 @@ private function resetPageAndChildren($pageId): void
      */
     private function selfCallback($method)
     {
-        return function () use ($method) {
-            return \call_user_func_array(
-                [$this, $method],
-                \func_get_args()
-            );
-        };
+        return fn () => \call_user_func_array(
+            [$this, $method],
+            \func_get_args()
+        );
     }
 }
diff --git a/src/EventListener/DataContainer/ParentTableListener.php b/src/EventListener/DataContainer/ParentTableListener.php
index 0cdd910..fb1b774 100644
--- a/src/EventListener/DataContainer/ParentTableListener.php
+++ b/src/EventListener/DataContainer/ParentTableListener.php
@@ -12,10 +12,7 @@
 
 class ParentTableListener
 {
-    /**
-     * @var string
-     */
-    private $table;
+    private string $table;
 
     /**
      * Constructor.
@@ -37,9 +34,7 @@ public function register(): void
             'label' => &$GLOBALS['TL_LANG'][$this->table]['master'],
             'exclude' => true,
             'inputType' => 'select',
-            'options_callback' => function (DataContainer $dc) {
-                return $this->onMasterOptions($dc);
-            },
+            'options_callback' => fn (DataContainer $dc) => $this->onMasterOptions($dc),
             'eval' => [
                 'includeBlankOption' => true,
                 'blankOptionLabel' => &$GLOBALS['TL_LANG'][$this->table]['isMaster'],
diff --git a/src/EventListener/DataContainer/UserLabelsListener.php b/src/EventListener/DataContainer/UserLabelsListener.php
index 6a553cf..be6cd14 100644
--- a/src/EventListener/DataContainer/UserLabelsListener.php
+++ b/src/EventListener/DataContainer/UserLabelsListener.php
@@ -12,10 +12,7 @@
  */
 class UserLabelsListener
 {
-    /**
-     * @var Connection
-     */
-    private $connection;
+    private Connection $connection;
 
     public function __construct(Connection $connection)
     {
diff --git a/src/FrontendModule/ChangeLanguageModule.php b/src/FrontendModule/ChangeLanguageModule.php
index 41004b1..448d29f 100755
--- a/src/FrontendModule/ChangeLanguageModule.php
+++ b/src/FrontendModule/ChangeLanguageModule.php
@@ -33,10 +33,7 @@ class ChangeLanguageModule extends Module
      */
     protected $strTemplate = 'mod_changelanguage';
 
-    /**
-     * @var AlternateLinks
-     */
-    private static $alternateLinks;
+    private static ?AlternateLinks $alternateLinks = null;
 
     /**
      * @return AlternateLinks
diff --git a/src/Helper/AlternateLinks.php b/src/Helper/AlternateLinks.php
index 98016a7..3c54862 100644
--- a/src/Helper/AlternateLinks.php
+++ b/src/Helper/AlternateLinks.php
@@ -15,10 +15,7 @@
  */
 class AlternateLinks
 {
-    /**
-     * @var array
-     */
-    private $links = [];
+    private array $links = [];
 
     /**
      * Returns whether a link already exists for a language.
diff --git a/src/Helper/LanguageText.php b/src/Helper/LanguageText.php
index b429eac..8b3c0db 100644
--- a/src/Helper/LanguageText.php
+++ b/src/Helper/LanguageText.php
@@ -13,10 +13,7 @@
  */
 class LanguageText
 {
-    /**
-     * @var array
-     */
-    private $map = [];
+    private array $map = [];
 
     /**
      * Constructor.
diff --git a/src/Navigation/NavigationFactory.php b/src/Navigation/NavigationFactory.php
index e005c6d..a5514e9 100644
--- a/src/Navigation/NavigationFactory.php
+++ b/src/Navigation/NavigationFactory.php
@@ -10,20 +10,11 @@
 
 class NavigationFactory
 {
-    /**
-     * @var PageFinder
-     */
-    private $pageFinder;
+    private PageFinder $pageFinder;
 
-    /**
-     * @var LanguageText
-     */
-    private $languageText;
+    private LanguageText $languageText;
 
-    /**
-     * @var PageModel
-     */
-    private $currentPage;
+    private PageModel $currentPage;
 
     /**
      * Constructor.
diff --git a/src/Navigation/NavigationItem.php b/src/Navigation/NavigationItem.php
index c282bba..e212ff4 100644
--- a/src/Navigation/NavigationItem.php
+++ b/src/Navigation/NavigationItem.php
@@ -10,35 +10,17 @@
 
 class NavigationItem
 {
-    /**
-     * @var PageModel
-     */
-    private $rootPage;
+    private PageModel $rootPage;
 
-    /**
-     * @var PageModel|null
-     */
-    private $targetPage;
+    private ?PageModel $targetPage = null;
 
-    /**
-     * @var string
-     */
-    private $linkLabel;
+    private string $linkLabel;
 
-    /**
-     * @var bool
-     */
-    private $newWindow;
+    private ?bool $newWindow = null;
 
-    /**
-     * @var bool
-     */
-    private $isDirectFallback = false;
+    private bool $isDirectFallback = false;
 
-    /**
-     * @var bool
-     */
-    private $isCurrentPage = false;
+    private bool $isCurrentPage = false;
 
     /**
      * Constructor.
diff --git a/src/Navigation/UrlParameterBag.php b/src/Navigation/UrlParameterBag.php
index 53b19ef..edc4852 100644
--- a/src/Navigation/UrlParameterBag.php
+++ b/src/Navigation/UrlParameterBag.php
@@ -6,15 +6,9 @@
 
 class UrlParameterBag
 {
-    /**
-     * @var array
-     */
-    private $attributes;
+    private array $attributes;
 
-    /**
-     * @var array
-     */
-    private $query;
+    private array $query;
 
     /**
      * Constructor.
diff --git a/tools/rector/composer.json b/tools/rector/composer.json
new file mode 100644
index 0000000..aabf487
--- /dev/null
+++ b/tools/rector/composer.json
@@ -0,0 +1,5 @@
+{
+    "require": {
+        "rector/rector": "^0.12"
+    }
+}
diff --git a/tools/rector/composer.lock b/tools/rector/composer.lock
new file mode 100644
index 0000000..afde269
--- /dev/null
+++ b/tools/rector/composer.lock
@@ -0,0 +1,138 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "1b172c779330acfc362f492ece0e0604",
+    "packages": [
+        {
+            "name": "phpstan/phpstan",
+            "version": "1.9.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpstan.git",
+                "reference": "d6fdf01c53978b6429f1393ba4afeca39cc68afa"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/d6fdf01c53978b6429f1393ba4afeca39cc68afa",
+                "reference": "d6fdf01c53978b6429f1393ba4afeca39cc68afa",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2|^8.0"
+            },
+            "conflict": {
+                "phpstan/phpstan-shim": "*"
+            },
+            "bin": [
+                "phpstan",
+                "phpstan.phar"
+            ],
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "PHPStan - PHP Static Analysis Tool",
+            "keywords": [
+                "dev",
+                "static analysis"
+            ],
+            "support": {
+                "issues": "https://github.com/phpstan/phpstan/issues",
+                "source": "https://github.com/phpstan/phpstan/tree/1.9.2"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/ondrejmirtes",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/phpstan",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/phpstan/phpstan",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2022-11-10T09:56:11+00:00"
+        },
+        {
+            "name": "rector/rector",
+            "version": "0.12.23",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/rectorphp/rector.git",
+                "reference": "690b31768b322db886b35845f8452025eba2cacb"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/rectorphp/rector/zipball/690b31768b322db886b35845f8452025eba2cacb",
+                "reference": "690b31768b322db886b35845f8452025eba2cacb",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2|^8.0",
+                "phpstan/phpstan": "^1.6"
+            },
+            "conflict": {
+                "phpstan/phpdoc-parser": "<1.2",
+                "rector/rector-cakephp": "*",
+                "rector/rector-doctrine": "*",
+                "rector/rector-laravel": "*",
+                "rector/rector-nette": "*",
+                "rector/rector-phpoffice": "*",
+                "rector/rector-phpunit": "*",
+                "rector/rector-prefixed": "*",
+                "rector/rector-symfony": "*"
+            },
+            "bin": [
+                "bin/rector"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "0.12-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "Instant Upgrade and Automated Refactoring of any PHP code",
+            "support": {
+                "issues": "https://github.com/rectorphp/rector/issues",
+                "source": "https://github.com/rectorphp/rector/tree/0.12.23"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/tomasvotruba",
+                    "type": "github"
+                }
+            ],
+            "time": "2022-05-01T15:50:16+00:00"
+        }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": [],
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": [],
+    "plugin-api-version": "2.3.0"
+}
diff --git a/tools/rector/config.php b/tools/rector/config.php
new file mode 100644
index 0000000..f8cbf39
--- /dev/null
+++ b/tools/rector/config.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodeQuality\Rector\FuncCall\CompactToVariablesRector;
+use Rector\Config\RectorConfig;
+use Rector\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector;
+use Rector\Doctrine\Set\DoctrineSetList;
+use Rector\Php74\Rector\FuncCall\ArraySpreadInsteadOfArrayMergeRector;
+use Rector\Php74\Rector\Property\RestoreDefaultNullToNullableTypePropertyRector;
+use Rector\Php74\Rector\Property\TypedPropertyRector;
+use Rector\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector;
+use Rector\Php80\Rector\Switch_\ChangeSwitchToMatchRector;
+use Rector\Set\ValueObject\LevelSetList;
+use Rector\Symfony\Set\SymfonyLevelSetList;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->paths([
+        __DIR__ . '/../../src',
+    ]);
+
+    $rectorConfig->skip([
+        ClassPropertyAssignToConstructorPromotionRector::class => [
+            '/src/Entity/*',
+        ],
+        ChangeSwitchToMatchRector::class,
+    ]);
+
+    $services = $rectorConfig->services();
+    $services->set(ArraySpreadInsteadOfArrayMergeRector::class);
+    $services->set(CompactToVariablesRector::class);
+    $services->set(RemoveUnusedPrivateMethodParameterRector::class);
+    $services->set(RestoreDefaultNullToNullableTypePropertyRector::class);
+    $services->set(TypedPropertyRector::class);
+
+    $rectorConfig->sets([
+        LevelSetList::UP_TO_PHP_74,
+        DoctrineSetList::DOCTRINE_DBAL_30,
+        DoctrineSetList::DOCTRINE_ORM_29,
+        SymfonyLevelSetList::UP_TO_SYMFONY_54,
+    ]);
+};