diff --git a/lib/private/AppFramework/Http/Dispatcher.php b/lib/private/AppFramework/Http/Dispatcher.php
index fdf99a5784..965d340fc7 100644
--- a/lib/private/AppFramework/Http/Dispatcher.php
+++ b/lib/private/AppFramework/Http/Dispatcher.php
@@ -167,10 +167,14 @@ class Dispatcher {
 			// if none is given try the first Accept header
 			if($format === null) {
 				$headers = $this->request->getHeader('Accept');
-				$format = $controller->getResponderByHTTPHeader($headers);
+				$format = $controller->getResponderByHTTPHeader($headers, null);
 			}
 
-			$response = $controller->buildResponse($response, $format);
+			if ($format !== null) {
+				$response = $controller->buildResponse($response, $format);
+			} else {
+				$response = $controller->buildResponse($response);
+			}
 		}
 
 		return $response;
diff --git a/lib/private/AppFramework/Middleware/OCSMiddleware.php b/lib/private/AppFramework/Middleware/OCSMiddleware.php
index 2c7d1167e7..b21e8e05a9 100644
--- a/lib/private/AppFramework/Middleware/OCSMiddleware.php
+++ b/lib/private/AppFramework/Middleware/OCSMiddleware.php
@@ -72,7 +72,7 @@ class OCSMiddleware extends Middleware {
 		// if none is given try the first Accept header
 		if($format === null) {
 			$headers = $this->request->getHeader('Accept');
-			$format = $controller->getResponderByHTTPHeader($headers);
+			$format = $controller->getResponderByHTTPHeader($headers, 'xml');
 		}
 
 		return $format;
diff --git a/lib/public/AppFramework/Controller.php b/lib/public/AppFramework/Controller.php
index daf6018cd1..c6baa5e30c 100644
--- a/lib/public/AppFramework/Controller.php
+++ b/lib/public/AppFramework/Controller.php
@@ -104,8 +104,9 @@ abstract class Controller {
 	 * @param string $acceptHeader
 	 * @return string the responder type
 	 * @since 7.0.0
+	 * @since 9.1.0 Added default parameter
 	 */
-	public function getResponderByHTTPHeader($acceptHeader) {
+	public function getResponderByHTTPHeader($acceptHeader, $default='json') {
 		$headers = explode(',', $acceptHeader);
 
 		// return the first matching responder
@@ -119,8 +120,8 @@ abstract class Controller {
 			}
 		}
 
-		// no matching header defaults to json
-		return 'json';
+		// no matching header return default
+		return $default;
 	}
 
 
diff --git a/lib/public/AppFramework/OCSController.php b/lib/public/AppFramework/OCSController.php
index e118b34250..e67c0fc21a 100644
--- a/lib/public/AppFramework/OCSController.php
+++ b/lib/public/AppFramework/OCSController.php
@@ -31,6 +31,7 @@ namespace OCP\AppFramework;
 
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\Http\OCSResponse;
+use OCP\AppFramework\Http\Response;
 use OCP\IRequest;
 
 
@@ -69,6 +70,19 @@ abstract class OCSController extends ApiController {
 		});
 	}
 
+	/**
+	 * Since the OCS endpoints default to XML we need to find out the format
+	 * again
+	 * @param mixed $response the value that was returned from a controller and
+	 * is not a Response instance
+	 * @param string $format the format for which a formatter has been registered
+	 * @throws \DomainException if format does not match a registered formatter
+	 * @return Response
+	 * @since 9.1.0
+	 */
+	public function buildResponse($response, $format = 'xml') {
+		return parent::buildResponse($response, $format);
+	}
 
 	/**
 	 * Unwrap data and build ocs response