diff --git a/src/CliMiddleware.php b/src/CliMiddleware.php
index 2e92f56..d361f8d 100644
--- a/src/CliMiddleware.php
+++ b/src/CliMiddleware.php
@@ -21,7 +21,7 @@ class CliMiddleware implements MiddlewareInterface
     
     public ContainerInterface $container;
 
-    public null|CommandFetcher $fetcher;
+    public ?CommandFetcher $fetcher;
 
     public CommandStack $commands;
 
@@ -31,7 +31,7 @@ class CliMiddleware implements MiddlewareInterface
 
     protected array $parsedOptions = [];
 
-    public function __construct(ContainerInterface $container, callable $defaultResponseInterface = null, null|CommandFetcher $fetcher = null, null|CommandStack $stack = null, bool $allowAsciiFormatting = true) {
+    public function __construct(ContainerInterface $container, ? callable $defaultResponseInterface = null, ?CommandFetcher $fetcher = null, ?CommandStack $stack = null, bool $allowAsciiFormatting = true) {
         $this->defaultResponse = $defaultResponseInterface;
         $this->container = $container;
         $this->fetcher = $fetcher;