diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index 96e46e57..e933cc31 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -15,7 +15,7 @@
 $config->setRules(
     PedroTroller\CS\Fixer\RuleSetFactory::create()
         ->phpCsFixer(true)
-        ->php(8.0, true)
+        ->php(8.1, true)
         ->pedrotroller(true)
         ->enable('align_multiline_comment')
         ->enable('array_indentation')
diff --git a/.scrutinizer.yml b/.scrutinizer.yml
index 7766f44d..cf26443c 100644
--- a/.scrutinizer.yml
+++ b/.scrutinizer.yml
@@ -4,7 +4,7 @@ build:
     analysis:
       environment:
         php:
-          version: 8.0.2
+          version: 8.2.16
       tests:
         override:
           - php-scrutinizer-run
diff --git a/README.md b/README.md
index 0a82bd85..c5987864 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ Are you often tired to repeat static choices like gender or civility in your app
 
 ## Requirements
 
-- PHP >= 8.0
+- PHP >= 8.1
 - Symfony 5.4 or 6.*
 
 ## Installation
diff --git a/composer.json b/composer.json
index 67722a12..bbb27092 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
         }
     ],
     "require": {
-        "php": ">=8.0",
+        "php": ">=8.1",
         "symfony/config": "^5.4 || ^6.2@dev",
         "symfony/dependency-injection": "^5.4 || ^6.2@dev",
         "symfony/form": "^5.4 || ^6.2@dev",
diff --git a/rector.php b/rector.php
index 15405a8b..218ca791 100644
--- a/rector.php
+++ b/rector.php
@@ -3,29 +3,9 @@
 declare(strict_types=1);
 
 use Rector\Config\RectorConfig;
-use Rector\Core\ValueObject\PhpVersion;
 use Rector\Set\ValueObject\LevelSetList;
 
 return static function (RectorConfig $rectorConfig): void {
-    $rectorConfig
-        ->paths(
-            [
-                __DIR__.'/src',
-            ]
-        )
-    ;
-
-    $rectorConfig
-        ->phpVersion(
-            PhpVersion::PHP_80
-        )
-    ;
-
-    $rectorConfig
-        ->sets(
-            [
-                LevelSetList::UP_TO_PHP_80,
-            ]
-        )
-    ;
+    $rectorConfig->paths([__DIR__.'/src']);
+    $rectorConfig->sets([LevelSetList::UP_TO_PHP_81]);
 };
diff --git a/src/Knp/DictionaryBundle/Dictionary/Factory/Extended.php b/src/Knp/DictionaryBundle/Dictionary/Factory/Extended.php
index 70f90875..8146a78f 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Factory/Extended.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Factory/Extended.php
@@ -12,7 +12,7 @@
 
 final class Extended implements Factory
 {
-    public function __construct(private Factory $factory, private Collection $dictionaries) {}
+    public function __construct(private readonly Factory $factory, private Collection $dictionaries) {}
 
     public function create(string $name, array $config): Dictionary
     {
diff --git a/src/Knp/DictionaryBundle/Dictionary/Factory/Invokable.php b/src/Knp/DictionaryBundle/Dictionary/Factory/Invokable.php
index b9edfe49..85b2a97f 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Factory/Invokable.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Factory/Invokable.php
@@ -11,7 +11,7 @@
 
 final class Invokable implements Factory
 {
-    public function __construct(private ContainerInterface $container) {}
+    public function __construct(private readonly ContainerInterface $container) {}
 
     /**
      * {@inheritdoc}
diff --git a/src/Knp/DictionaryBundle/Dictionary/Factory/Iterator.php b/src/Knp/DictionaryBundle/Dictionary/Factory/Iterator.php
index b69964de..e6f952c9 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Factory/Iterator.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Factory/Iterator.php
@@ -12,7 +12,7 @@
 
 final class Iterator implements Factory
 {
-    public function __construct(private ContainerInterface $container) {}
+    public function __construct(private readonly ContainerInterface $container) {}
 
     /**
      * {@inheritdoc}
diff --git a/src/Knp/DictionaryBundle/Dictionary/Factory/KeyValue.php b/src/Knp/DictionaryBundle/Dictionary/Factory/KeyValue.php
index 9a53a488..a3e0d8ed 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Factory/KeyValue.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Factory/KeyValue.php
@@ -12,7 +12,7 @@
 
 final class KeyValue implements Factory
 {
-    public function __construct(private ValueTransformer $transformer) {}
+    public function __construct(private readonly ValueTransformer $transformer) {}
 
     /**
      * {@inheritdoc}
diff --git a/src/Knp/DictionaryBundle/Dictionary/Factory/Value.php b/src/Knp/DictionaryBundle/Dictionary/Factory/Value.php
index 8376c0a9..03a0ae36 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Factory/Value.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Factory/Value.php
@@ -12,7 +12,7 @@
 
 final class Value implements Factory
 {
-    public function __construct(private ValueTransformer $transformer) {}
+    public function __construct(private readonly ValueTransformer $transformer) {}
 
     /**
      * {@inheritdoc}
diff --git a/src/Knp/DictionaryBundle/Dictionary/Factory/ValueAsKey.php b/src/Knp/DictionaryBundle/Dictionary/Factory/ValueAsKey.php
index 6c2344f8..4ad16a01 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Factory/ValueAsKey.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Factory/ValueAsKey.php
@@ -12,7 +12,7 @@
 
 final class ValueAsKey implements Factory
 {
-    public function __construct(private ValueTransformer $transformer) {}
+    public function __construct(private readonly ValueTransformer $transformer) {}
 
     /**
      * {@inheritdoc}
diff --git a/src/Knp/DictionaryBundle/Dictionary/Invokable.php b/src/Knp/DictionaryBundle/Dictionary/Invokable.php
index b178fddb..51b4fe72 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Invokable.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Invokable.php
@@ -31,8 +31,11 @@ final class Invokable implements Dictionary
     /**
      * @param mixed[] $callableArgs
      */
-    public function __construct(private string $name, callable $callable, private array $callableArgs = [])
-    {
+    public function __construct(
+        private readonly string $name,
+        callable $callable,
+        private readonly array $callableArgs = []
+    ) {
         $this->callable = $callable;
     }
 
diff --git a/src/Knp/DictionaryBundle/Dictionary/Simple.php b/src/Knp/DictionaryBundle/Dictionary/Simple.php
index e66f9aaa..005d99bb 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Simple.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Simple.php
@@ -17,7 +17,7 @@ final class Simple implements Dictionary
     /**
      * @param array<mixed, E> $values
      */
-    public function __construct(private string $name, private array $values) {}
+    public function __construct(private readonly string $name, private array $values) {}
 
     public function getName(): string
     {
diff --git a/src/Knp/DictionaryBundle/Dictionary/Traceable.php b/src/Knp/DictionaryBundle/Dictionary/Traceable.php
index 9994d705..11933553 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Traceable.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Traceable.php
@@ -17,7 +17,10 @@ final class Traceable implements Dictionary
     /**
      * @param Dictionary<E> $dictionary
      */
-    public function __construct(private Dictionary $dictionary, private DictionaryDataCollector $collector) {}
+    public function __construct(
+        private readonly Dictionary $dictionary,
+        private readonly DictionaryDataCollector $collector
+    ) {}
 
     public function getName(): string
     {
diff --git a/src/Knp/DictionaryBundle/Dictionary/Wrapper.php b/src/Knp/DictionaryBundle/Dictionary/Wrapper.php
index 095cc83d..e2b299e3 100644
--- a/src/Knp/DictionaryBundle/Dictionary/Wrapper.php
+++ b/src/Knp/DictionaryBundle/Dictionary/Wrapper.php
@@ -16,7 +16,7 @@ abstract class Wrapper implements Dictionary
     /**
      * @param Dictionary<E> $wrapped
      */
-    public function __construct(private Dictionary $wrapped) {}
+    public function __construct(private readonly Dictionary $wrapped) {}
 
     public function getName(): string
     {
diff --git a/src/Knp/DictionaryBundle/Templating/Extension/Dictionary.php b/src/Knp/DictionaryBundle/Templating/Extension/Dictionary.php
index 30dd7b82..41965b37 100644
--- a/src/Knp/DictionaryBundle/Templating/Extension/Dictionary.php
+++ b/src/Knp/DictionaryBundle/Templating/Extension/Dictionary.php
@@ -19,7 +19,7 @@ public function __construct(private Collection $dictionaries) {}
     public function getFunctions()
     {
         return [
-            new TwigFunction('dictionary', [$this->dictionaries, 'offsetGet']),
+            new TwigFunction('dictionary', $this->dictionaries->offsetGet(...)),
         ];
     }
 
diff --git a/src/Knp/DictionaryBundle/Validator/Constraints/DictionaryValidator.php b/src/Knp/DictionaryBundle/Validator/Constraints/DictionaryValidator.php
index 7e4513ab..2af79633 100644
--- a/src/Knp/DictionaryBundle/Validator/Constraints/DictionaryValidator.php
+++ b/src/Knp/DictionaryBundle/Validator/Constraints/DictionaryValidator.php
@@ -12,7 +12,7 @@ final class DictionaryValidator extends ConstraintValidator
 {
     use DictionaryValidator\SymfonyCompatibilityTrait;
 
-    public function __construct(private Collection $dictionaries) {}
+    public function __construct(private readonly Collection $dictionaries) {}
 
     private function varToString(mixed $var): string
     {