diff --git a/src/Api/Serializer/QuerySerializer.php b/src/Api/Serializer/QuerySerializer.php
index 107e68ff62..f04c043c6e 100644
--- a/src/Api/Serializer/QuerySerializer.php
+++ b/src/Api/Serializer/QuerySerializer.php
@@ -54,7 +54,7 @@ public function __invoke(CommandInterface $command)
             );
         }
 
-        $body = http_build_query($body, null, '&', PHP_QUERY_RFC3986);
+        $body = http_build_query($body, '', '&', PHP_QUERY_RFC3986);
 
         return new Request(
             'POST',
diff --git a/src/CloudFront/UrlSigner.php b/src/CloudFront/UrlSigner.php
index 3d8f0ff622..3929c2f46b 100644
--- a/src/CloudFront/UrlSigner.php
+++ b/src/CloudFront/UrlSigner.php
@@ -64,7 +64,7 @@ public function getSignedUrl($url, $expires = null, $policy = null)
             $policy
         );
         $uri = $uri->withQuery(
-            http_build_query($query + $signature, null, '&', PHP_QUERY_RFC3986)
+            http_build_query($query + $signature, '', '&', PHP_QUERY_RFC3986)
         );
 
         return $scheme === 'rtmp'