diff --git a/Changelog.md b/Changelog.md
index ba65045..30ea150 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -2,6 +2,12 @@
 
 The change log describes what is "Added", "Removed", "Changed" or "Fixed" between each release.
 
+## 1.8.1
+
+### Fixed
+
+- Symfony 6 compatibility issues
+
 ## 1.8.0
 
 ### Added
diff --git a/psalm.baseline.xml b/psalm.baseline.xml
index eaaae28..260b1e0 100644
--- a/psalm.baseline.xml
+++ b/psalm.baseline.xml
@@ -1,5 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <files psalm-version="4.8.1@f73f2299dbc59a3e6c4d66cff4605176e728ee69">
+  <file src="src/AppKernel.php">
+    <InvalidReturnStatement occurrences="1">
+      <code>$bundles</code>
+    </InvalidReturnStatement>
+    <InvalidReturnType occurrences="1">
+      <code>iterable</code>
+    </InvalidReturnType>
+    <ReservedWord occurrences="1">
+      <code>$loader-&gt;getResolver()-&gt;resolve($file, 'php')</code>
+    </ReservedWord>
+    <UndefinedClass occurrences="1">
+      <code>RouteCollectionBuilder</code>
+    </UndefinedClass>
+  </file>
   <file src="src/BaseBundleTestCase.php">
     <UndefinedClass occurrences="1">
       <code>ResettableContainerInterface</code>
diff --git a/src/AppKernel.php b/src/AppKernel.php
index 71aa4d1..2a0817d 100644
--- a/src/AppKernel.php
+++ b/src/AppKernel.php
@@ -8,6 +8,9 @@
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\HttpKernel\Kernel;
+use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
+use Symfony\Component\Routing\Loader\PhpFileLoader as RoutingPhpFileLoader;
+use Symfony\Component\Routing\RouteCollection;
 use Symfony\Component\Routing\RouteCollectionBuilder;
 
 /**
@@ -79,17 +82,17 @@ public function addConfigFile($configFile)
         $this->configFiles[] = $configFile;
     }
 
-    public function getCacheDir()
+    public function getCacheDir(): string
     {
         return sys_get_temp_dir().'/NyholmBundleTest/'.$this->cachePrefix;
     }
 
-    public function getLogDir()
+    public function getLogDir(): string
     {
         return sys_get_temp_dir().'/NyholmBundleTest/log';
     }
 
-    public function getProjectDir()
+    public function getProjectDir(): string
     {
         if (null === $this->fakedProjectDir) {
             return realpath(__DIR__.'/../../../../');
@@ -114,7 +117,7 @@ public function setProjectDir($projectDir)
         $this->fakedProjectDir = $projectDir;
     }
 
-    public function registerBundles()
+    public function registerBundles(): iterable
     {
         $this->bundlesToRegister = array_unique($this->bundlesToRegister);
         $bundles = [];
@@ -169,21 +172,40 @@ public function registerContainerConfiguration(LoaderInterface $loader)
      */
     public function loadRoutes(LoaderInterface $loader)
     {
-        $routes = new RouteCollectionBuilder($loader);
+        if (class_exists(RoutingConfigurator::class)) {
+            $file = (new \ReflectionObject($this))->getFileName();
+            /** @var RoutingPhpFileLoader $kernelLoader */
+            $kernelLoader = $loader->getResolver()->resolve($file, 'php');
+            $kernelLoader->setCurrentDir(\dirname($file));
+
+            $collection = new RouteCollection();
+            $configurator = new RoutingConfigurator($collection, $kernelLoader, $file, $file, $this->getEnvironment());
+
+            if ($this->routingFile) {
+                $configurator->import($this->routingFile);
+            } else {
+                $configurator->import(__DIR__.'/config/routing.yml');
+            }
 
-        if ($this->routingFile) {
-            $routes->import($this->routingFile);
+            return $collection;
         } else {
-            $routes->import(__DIR__.'/config/routing.yml');
-        }
+            // Legacy
+            $routes = new RouteCollectionBuilder($loader);
 
-        return $routes->build();
+            if ($this->routingFile) {
+                $routes->import($this->routingFile);
+            } else {
+                $routes->import(__DIR__.'/config/routing.yml');
+            }
+
+            return $routes->build();
+        }
     }
 
     /**
      * {@inheritdoc}
      */
-    protected function buildContainer()
+    protected function buildContainer(): ContainerBuilder
     {
         $container = parent::buildContainer();