diff --git a/composer.json b/composer.json
index 421d772..bd84903 100644
--- a/composer.json
+++ b/composer.json
@@ -36,7 +36,7 @@
         "php": "^8.1",
 
         "simplesamlphp/assert": "^1.0.0",
-        "simplesamlphp/simplesamlphp": "^2.2.0",
+        "simplesamlphp/simplesamlphp": "dev-bugfix/discopwer-duplicate-date-header",
         "simplesamlphp/composer-module-installer": "^1.3.4",
         "symfony/http-foundation": "^6.4.0"
     },
diff --git a/src/Controller/DiscoPower.php b/src/Controller/DiscoPower.php
index 599b459..03c3bef 100644
--- a/src/Controller/DiscoPower.php
+++ b/src/Controller/DiscoPower.php
@@ -8,15 +8,15 @@
 use SimpleSAML\Error;
 use SimpleSAML\Module\discopower\PowerIdPDisco;
 use SimpleSAML\Session;
-use Symfony\Component\HttpFoundation\{JsonResponse, Request, Response, StreamedResponse};
+use Symfony\Component\HttpFoundation\{JsonResponse, Request, Response};
 
 class DiscoPower
 {
     /**
      * @param \Symfony\Component\HttpFoundation\Request $request The current request.
-     * @return \Symfony\Component\HttpFoundation\StreamedResponse
+     * @return \Symfony\Component\HttpFoundation\Response
      */
-    public function main(Request $request): StreamedResponse
+    public function main(Request $request): Response
     {
         try {
             $discoHandler = new PowerIdPDisco(
@@ -29,7 +29,7 @@ public function main(Request $request): StreamedResponse
         }
 
         try {
-            return new StreamedResponse([$discoHandler, 'handleRequest']);
+            return $discoHandler->handleRequest();
         } catch (Exception $exception) {
             // An error here should be caused by metadata
             throw new Error\Error('METADATA', $exception);
diff --git a/src/PowerIdPDisco.php b/src/PowerIdPDisco.php
index 82cd127..f462f60 100644
--- a/src/PowerIdPDisco.php
+++ b/src/PowerIdPDisco.php
@@ -13,6 +13,7 @@
 use SimpleSAML\Utils;
 use SimpleSAML\XHTML\IdPDisco;
 use SimpleSAML\XHTML\Template;
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * This class implements a generic IdP discovery service, for use in various IdP discovery service pages. This should
@@ -289,10 +290,16 @@ protected function filterList(array $list): array
      * Handles a request to this discovery service.
      *
      * The IdP disco parameters should be set before calling this function.
+     *
+     * @return \Symfony\Component\HttpFoundation\Response
      */
-    public function handleRequest(): void
+    public function handleRequest(): Response
     {
         $this->start();
+        $result = $this->start();
+        if ($result !== null) {
+            return $result;
+        }
 
         // no choice made. Show discovery service page
         $idpList = $this->getIdPList();
@@ -344,7 +351,7 @@ public function handleRequest(): void
                 $t->data['tabNames'][$tab] = $translator::noop($translatableTag);
             }
         }
-        $t->send();
+        return $t;
     }