diff --git a/.github/workflows/code_samples.yaml b/.github/workflows/code_samples.yaml
index 5ab0edcf371..d410a86455d 100644
--- a/.github/workflows/code_samples.yaml
+++ b/.github/workflows/code_samples.yaml
@@ -10,7 +10,8 @@ jobs:
         strategy:
             matrix:
                 php:
-                    - "8.3"
+                    - "8.4" # Upper supported version
+                    - "8.3" # Lower supported version
         steps:
             - uses: actions/checkout@v4
 
@@ -46,11 +47,11 @@ jobs:
             - name: Run PHPStan analysis
               run: composer phpstan
 
-            - name: Deptrac
+            - name: Run Deptrac analysis
               run: composer deptrac
 
-            - name: Run rector
-              run: vendor/bin/rector process --dry-run --ansi
+            - name: Run Rector check
+              run: composer check-rector
 
     code-samples-inclusion-check:
         name: Check code samples inclusion
diff --git a/code_samples/back_office/search/src/Search/Serializer/Normalizer/Suggestion/ProductSuggestionNormalizer.php b/code_samples/back_office/search/src/Search/Serializer/Normalizer/Suggestion/ProductSuggestionNormalizer.php
index 86d37860e96..8291280647c 100644
--- a/code_samples/back_office/search/src/Search/Serializer/Normalizer/Suggestion/ProductSuggestionNormalizer.php
+++ b/code_samples/back_office/search/src/Search/Serializer/Normalizer/Suggestion/ProductSuggestionNormalizer.php
@@ -16,7 +16,7 @@ class ProductSuggestionNormalizer implements
     /**
      * @return array<string, string|null>
      */
-    public function normalize($object, string $format = null, array $context = []): array
+    public function normalize($object, ?string $format = null, array $context = []): array
     {
         /** @var \App\Search\Model\Suggestion\ProductSuggestion $object */
         return [
diff --git a/code_samples/data_migration/src/Migrations/Action/AssignSectionDenormalizer.php b/code_samples/data_migration/src/Migrations/Action/AssignSectionDenormalizer.php
index a8b914701fc..96f067a99e8 100644
--- a/code_samples/data_migration/src/Migrations/Action/AssignSectionDenormalizer.php
+++ b/code_samples/data_migration/src/Migrations/Action/AssignSectionDenormalizer.php
@@ -9,7 +9,7 @@
 
 final class AssignSectionDenormalizer extends AbstractActionDenormalizer
 {
-    protected function supportsActionName(string $actionName, string $format = null): bool
+    protected function supportsActionName(string $actionName, ?string $format = null): bool
     {
         return $actionName === AssignSection::TYPE;
     }
@@ -22,7 +22,7 @@ protected function supportsActionName(string $actionName, string $format = null)
      *
      * @return \App\Migrations\Action\AssignSection
      */
-    public function denormalize($data, string $type, string $format = null, array $context = []): AssignSection
+    public function denormalize($data, string $type, ?string $format = null, array $context = []): AssignSection
     {
         Assert::keyExists($data, 'value');
 
diff --git a/code_samples/data_migration/src/Migrations/Step/ReplaceNameStepNormalizer.php b/code_samples/data_migration/src/Migrations/Step/ReplaceNameStepNormalizer.php
index 54249074267..55b5ace82d9 100644
--- a/code_samples/data_migration/src/Migrations/Step/ReplaceNameStepNormalizer.php
+++ b/code_samples/data_migration/src/Migrations/Step/ReplaceNameStepNormalizer.php
@@ -14,7 +14,7 @@ final class ReplaceNameStepNormalizer extends AbstractStepNormalizer
 {
     protected function normalizeStep(
         StepInterface $object,
-        string $format = null,
+        ?string $format = null,
         array $context = []
     ): array {
         assert($object instanceof ReplaceNameStep);
diff --git a/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueDenormalizer.php b/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueDenormalizer.php
index 96b2b844970..f4037480158 100644
--- a/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueDenormalizer.php
+++ b/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueDenormalizer.php
@@ -8,7 +8,7 @@
 
 final class ValueDenormalizer implements DenormalizerInterface
 {
-    public function denormalize($data, string $class, string $format = null, array $context = []): mixed
+    public function denormalize($data, string $class, ?string $format = null, array $context = []): mixed
     {
         if (isset($data['x']) && isset($data['y'])) {
             // Support for old format
diff --git a/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueNormalizer.php b/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueNormalizer.php
index c21c39b2118..bc7fea2b9c6 100644
--- a/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueNormalizer.php
+++ b/code_samples/field_types/2dpoint_ft/src/Serializer/Point2D/ValueNormalizer.php
@@ -11,7 +11,7 @@ final class ValueNormalizer implements NormalizerInterface
     /**
      * @return array<?float, ?float>
      */
-    public function normalize($object, string $format = null, array $context = []): array
+    public function normalize($object, ?string $format = null, array $context = []): array
     {
         return [
             $object->getX(),
diff --git a/composer.json b/composer.json
index a55f3ca6ce2..1f8cb44b1e2 100644
--- a/composer.json
+++ b/composer.json
@@ -88,13 +88,15 @@
         "fix-cs": "php-cs-fixer fix --config=.php-cs-fixer.php -v --show-progress=dots",
         "check-cs": "@fix-cs --dry-run",
         "phpstan": "phpstan analyse",
-        "deptrac": "deptrac analyse"
+        "deptrac": "deptrac analyse",
+        "check-rector": "rector process --dry-run --ansi"
     },
     "scripts-descriptions": {
         "fix-cs": "Automatically fixes code style in all files",
         "check-cs": "Run code style checker for all files",
         "phpstan": "Run static code analysis",
-        "deptrac": "Run Deptrac architecture testing"
+        "deptrac": "Run Deptrac architecture testing",
+        "check-rector": "Check for code refactoring opportunities"
     },
     "config": {
         "allow-plugins": false