diff --git a/src/Resources/skeleton/validator/Constraint.tpl.php b/src/Resources/skeleton/validator/Constraint.tpl.php
index 991ad9424..7baafa472 100644
--- a/src/Resources/skeleton/validator/Constraint.tpl.php
+++ b/src/Resources/skeleton/validator/Constraint.tpl.php
@@ -16,5 +16,5 @@ class <?= $class_name ?> extends Constraint
      * Any public properties become valid options for the annotation.
      * Then, use these in your validator class.
      */
-    public $message = 'The value "{{ value }}" is not valid.';
+    public string $message = 'The value "{{ value }}" is not valid.';
 }
diff --git a/src/Resources/skeleton/validator/Validator.tpl.php b/src/Resources/skeleton/validator/Validator.tpl.php
index 0656d4cb4..ccc1a00f9 100644
--- a/src/Resources/skeleton/validator/Validator.tpl.php
+++ b/src/Resources/skeleton/validator/Validator.tpl.php
@@ -7,7 +7,7 @@
 
 class <?= $class_name ?> extends ConstraintValidator
 {
-    public function validate($value, Constraint $constraint)
+    public function validate(mixed $value, Constraint $constraint): void
     {
         /** @var <?= $constraint_class_name ?> $constraint */