diff --git a/rector.php b/rector.php
index 41059c1..2aafe61 100644
--- a/rector.php
+++ b/rector.php
@@ -12,8 +12,8 @@
         __DIR__ . '/tests',
     ])
     ->withSets([
-        LevelSetList::UP_TO_PHP_80,
-        SymfonySetList::SYMFONY_60,
+        LevelSetList::UP_TO_PHP_81,
+        SymfonySetList::SYMFONY_61,
     ])
     ->withImportNames(
         importShortClasses: false,
diff --git a/src/BooleanToYesNoSubscriber.php b/src/BooleanToYesNoSubscriber.php
index 125694f..70779c0 100644
--- a/src/BooleanToYesNoSubscriber.php
+++ b/src/BooleanToYesNoSubscriber.php
@@ -35,7 +35,7 @@ class BooleanToYesNoSubscriber implements EventSubscriberInterface
 {
     public function __construct(
         /** @var string[] */
-        private array $fieldNames
+        private readonly array $fieldNames
     ) {
     }
 
diff --git a/src/JsonSchemaSubscriber.php b/src/JsonSchemaSubscriber.php
index c2d7dbb..0b79000 100644
--- a/src/JsonSchemaSubscriber.php
+++ b/src/JsonSchemaSubscriber.php
@@ -34,7 +34,7 @@
 class JsonSchemaSubscriber implements EventSubscriberInterface
 {
     public function __construct(
-        private string $fieldName = 'schema'
+        private readonly string $fieldName = 'schema'
     ) {
     }