diff --git a/libs/async/include/psemek/async/future.hpp b/libs/async/include/psemek/async/future.hpp
index d80e992f..ecefbcea 100644
--- a/libs/async/include/psemek/async/future.hpp
+++ b/libs/async/include/psemek/async/future.hpp
@@ -30,7 +30,7 @@ namespace psemek::async
 		template <typename T>
 		struct then_function
 		{
-			using type = util::function<void(T)>;
+			using type = util::function<void(T &)>;
 		};
 
 		template <>