diff --git a/src/Debugger/Logger.php b/src/Debugger/Logger.php
index 9477d2b..eaac6d6 100644
--- a/src/Debugger/Logger.php
+++ b/src/Debugger/Logger.php
@@ -28,7 +28,7 @@ public function __construct(LoggerInterface $logger)
      * @param Call $call
      * @param CallInfo | null $info
      */
-    public function debugCall(Call $call, CallInfo $info = null)
+    public function debugCall(Call $call, ?CallInfo $info = null)
     {
         $message = $call->hasException()
             ? 'Thrown exception: ' . $call->getException()->getMessage()
diff --git a/src/Operation/CommandOperation.php b/src/Operation/CommandOperation.php
index 78bd39f..064f61b 100644
--- a/src/Operation/CommandOperation.php
+++ b/src/Operation/CommandOperation.php
@@ -48,11 +48,11 @@ public function set($key, $value)
     
     
     /**
-     * @param UrlQuery $urlQuery
+     * @param UrlQuery|null $urlQuery
      * @param array $extra
      * @return string
      */
-    protected function buildUrlQuery(UrlQuery $urlQuery = null, array $extra = [])
+    protected function buildUrlQuery(?UrlQuery $urlQuery = null, array $extra = [])
     {
         $params = [];
         if (null !== $urlQuery) {