diff --git a/deltachat-ffi/deltachat.h b/deltachat-ffi/deltachat.h
index 42ca674e2..332f9d4db 100644
--- a/deltachat-ffi/deltachat.h
+++ b/deltachat-ffi/deltachat.h
@@ -5218,6 +5218,9 @@ void dc_event_unref(dc_event_t* event);
 
 /**
  * Chat ephemeral timer changed.
+ *
+ * @param data1 (int) chat_id
+ * @param data2 (int) Timer value in seconds or 0 for disabled timer
  */
 #define DC_EVENT_CHAT_EPHEMERAL_TIMER_MODIFIED 2021