diff --git a/rector/toPhp7.4.php b/rector/toPhp7.4.php
index 279b4558..f5c1f4ec 100755
--- a/rector/toPhp7.4.php
+++ b/rector/toPhp7.4.php
@@ -3,9 +3,13 @@
 declare(strict_types=1);
 
 use Rector\Config\RectorConfig;
+use Rector\DowngradePhp82\Rector\FunctionLike\DowngradeStandaloneNullTrueFalseReturnTypeRector;
 
 return RectorConfig::configure()
     ->withPaths([
         __DIR__ . '/../src',
     ])
+    ->withRules([
+        DowngradeStandaloneNullTrueFalseReturnTypeRector::class,
+    ])
     ->withDowngradeSets(php74: true);