diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 268769b..9fdfaf6 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -13,7 +13,7 @@ jobs:
       fail-fast: true
       matrix:
         os: [ ubuntu-latest ]
-        php: [ 8.1, 8.2, 8.3 ]
+        php: [ 8.1, 8.2, 8.3, 8.4 ]
         laravel: [10.*, 11.* ]
         stability: [ prefer-lowest, prefer-stable ]
         include:
diff --git a/src/Discover.php b/src/Discover.php
index 3cbad2c..12e11e0 100644
--- a/src/Discover.php
+++ b/src/Discover.php
@@ -50,7 +50,7 @@ public function __construct(
         ?DiscoverCacheDriver $cacheDriver = null,
         ?string $cacheId = null,
         bool $withChains = true,
-        Sort $sort = null,
+        ?Sort $sort = null,
         bool $reverseSorting = false,
         StructureParser $structureParser = new PhpTokenStructureParser(),
         ?string $reflectionBasePath = null,