diff --git a/src/event/DeferEvent.hxx b/src/event/DeferEvent.hxx
index b96c2fbac..d1e3326d0 100644
--- a/src/event/DeferEvent.hxx
+++ b/src/event/DeferEvent.hxx
@@ -38,7 +38,7 @@ class DeferEvent final
 
 	EventLoop &loop;
 
-	typedef BoundMethod<void() noexcept> Callback;
+	using Callback = BoundMethod<void() noexcept>;
 	const Callback callback;
 
 public: