diff --git a/sys/include/net/asymcute.h b/sys/include/net/asymcute.h
index 748fddd296..75d4ded323 100644
--- a/sys/include/net/asymcute.h
+++ b/sys/include/net/asymcute.h
@@ -30,6 +30,7 @@
  * - Gateway discovery process not implemented
  * - Last will feature not implemented
  * - No support for QoS level 2
+ * - No support for QoS level -1
  * - No support for wildcard characters in topic names when subscribing
  * - Actual granted QoS level on subscription is ignored
  *