diff --git a/src/DataCollector/RouteCollector.php b/src/DataCollector/RouteCollector.php
index 54b4f91..25e09ba 100644
--- a/src/DataCollector/RouteCollector.php
+++ b/src/DataCollector/RouteCollector.php
@@ -22,7 +22,7 @@ class RouteCollector extends DataCollector implements Renderable, AssetProvider
 
     // The HTML var dumper requires debug bar users to support the new inline assets, which not all
     // may support yet - so return false by default for now.
-    protected bool $useHtmlVarDumper = false;
+    protected $useHtmlVarDumper = false;
 
     public function __construct(RouterInterface $router, array $config)
     {