--- /dev/null
+++ ../src/PhpParser/Node/NodeFactory.php
@@ -44,10 +44,12 @@
 use Rector\Exception\ShouldNotHappenException;
 use Rector\NodeDecorator\PropertyTypeDecorator;
 use Rector\NodeTypeResolver\Node\AttributeKey;
+use Rector\Php\PhpVersionProvider;
 use Rector\PhpDocParser\NodeTraverser\SimpleCallableNodeTraverser;
 use Rector\PHPStanStaticTypeMapper\Enum\TypeKind;
 use Rector\PostRector\ValueObject\PropertyMetadata;
 use Rector\StaticTypeMapper\StaticTypeMapper;
+use Rector\ValueObject\PhpVersionFeature;
 /**
  * @see \Rector\Tests\PhpParser\Node\NodeFactoryTest
  */
@@ -79,10 +81,15 @@
      */
     private $simpleCallableNodeTraverser;
     /**
+     * @readonly
+     * @var \Rector\Php\PhpVersionProvider
+     */
+    private $phpVersionProvider;
+    /**
      * @var string
      */
     private const THIS = 'this';
-    public function __construct(BuilderFactory $builderFactory, PhpDocInfoFactory $phpDocInfoFactory, StaticTypeMapper $staticTypeMapper, PropertyTypeDecorator $propertyTypeDecorator, SimpleCallableNodeTraverser $simpleCallableNodeTraverser)
+    public function __construct(BuilderFactory $builderFactory, PhpDocInfoFactory $phpDocInfoFactory, StaticTypeMapper $staticTypeMapper, PropertyTypeDecorator $propertyTypeDecorator, SimpleCallableNodeTraverser $simpleCallableNodeTraverser, PhpVersionProvider $phpVersionProvider)
     {
         $this->builderFactory = $builderFactory;
         $this->phpDocInfoFactory = $phpDocInfoFactory;
@@ -89,6 +96,7 @@
         $this->staticTypeMapper = $staticTypeMapper;
         $this->propertyTypeDecorator = $propertyTypeDecorator;
         $this->simpleCallableNodeTraverser = $simpleCallableNodeTraverser;
+        $this->phpVersionProvider = $phpVersionProvider;
     }
     /**
      * @param string|ObjectReference::* $className
@@ -275,6 +283,10 @@
         $param = $paramBuilder->getNode();
         $propertyFlags = $propertyMetadata->getFlags();
         $param->flags = $propertyFlags !== 0 ? $propertyFlags : Class_::MODIFIER_PRIVATE;
+        // make readonly by default
+        if ($this->phpVersionProvider->isAtLeastPhpVersion(PhpVersionFeature::READONLY_PROPERTY)) {
+            $param->flags |= Class_::MODIFIER_READONLY;
+        }
         return $param;
     }
     public function createFalse() : ConstFetch