diff --git a/composer.json b/composer.json
index a11c140..541be5f 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
         "ext-json": "*",
         "ext-openssl": "*",
         "ext-curl": "*",
-        "guzzlehttp/guzzle": "^7.9"
+        "guzzlehttp/guzzle": "^8.0"
     },
     "license": "MIT",
     "autoload": {
diff --git a/src/HelloRequest/HelloRequest.php b/src/HelloRequest/HelloRequest.php
index 856baf3..779e862 100644
--- a/src/HelloRequest/HelloRequest.php
+++ b/src/HelloRequest/HelloRequest.php
@@ -76,7 +76,10 @@ public function fetchHeader(string $key, $default = null)
     private function getAllHeaders(): array
     {
         if (function_exists('getallheaders')) {
-            return getallheaders();
+            $headers = getallheaders();
+            if ($headers !== false) {
+                return $headers;
+            }
         }
 
         $headers = [];