diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 5ff3c82..4db0f6e 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        php: [8.1, 8.2, 8.3]
+        php: [8.1, 8.2, 8.3, 8.4]
         laravel: [9.*, 10.*, 11.*]
         exclude:
           - laravel: 11.*
diff --git a/src/Specification/CompositeSpecification.php b/src/Specification/CompositeSpecification.php
index 73345af..0de8d48 100644
--- a/src/Specification/CompositeSpecification.php
+++ b/src/Specification/CompositeSpecification.php
@@ -34,7 +34,7 @@ public function __call(string $name, array $arguments)
         return $result === $this->rootSpecification ? $this : $result;
     }
 
-    public function nested(string $field, Specification|Closure $factory = null): static
+    public function nested(string $field, null|Specification|Closure $factory = null): static
     {
         $spec = $factory instanceof Specification
             ? $factory