diff --git a/src/FbInstantArticlesServiceProvider.php b/src/FbInstantArticlesServiceProvider.php
index b4c769b..71ce9a1 100644
--- a/src/FbInstantArticlesServiceProvider.php
+++ b/src/FbInstantArticlesServiceProvider.php
@@ -20,7 +20,7 @@ class FbInstantArticlesServiceProvider extends ServiceProviderBase {
       $container->getDefinition('http_middleware.negotiation')
         ->addMethodCall('registerFormat', [
           'fbia_rss',
-          ['application/rss+xml'],
+          ['application/rss+xml; charset=utf-8'],
         ]);
     }
   }