diff --git a/system/src/Grav/Common/Processors/DebuggerAssetsProcessor.php b/system/src/Grav/Common/Processors/DebuggerAssetsProcessor.php
index 9ccc324db..5160711e4 100644
--- a/system/src/Grav/Common/Processors/DebuggerAssetsProcessor.php
+++ b/system/src/Grav/Common/Processors/DebuggerAssetsProcessor.php
@@ -9,6 +9,7 @@
 
 namespace Grav\Common\Processors;
 
+use Grav\Framework\Psr7\Response;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
 use Psr\Http\Server\RequestHandlerInterface;
@@ -18,12 +19,17 @@ class DebuggerAssetsProcessor extends ProcessorBase
     public $id = 'debugger_assets';
     public $title = 'Debugger Assets';
 
-    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler) : ResponseInterface
+    public function process(ServerRequestInterface $request = null, RequestHandlerInterface $handler = null) : ResponseInterface
     {
         $this->startTimer();
         $this->container['debugger']->addAssets();
         $this->stopTimer();
 
-        return $handler->handle($request);
+        // Backwards compatibility
+        if ($request && $handler) {
+            return $handler->handle($request);
+        } else {
+            return new Response();
+        }
     }
 }