diff --git a/src/server/i18n.h b/src/server/i18n.h
index 79005b72..36d4b955 100644
--- a/src/server/i18n.h
+++ b/src/server/i18n.h
@@ -93,7 +93,7 @@ private:
 
 } // namespace i18n
 
-struct ParameterizedMessage
+class ParameterizedMessage
 {
 public: // types
   typedef kainjow::mustache::object Parameters;