diff --git a/status/raw/status-app-protocols.md b/status/raw/status-app-protocols.md
index 7fa90f4f..1f7b4b84 100644
--- a/status/raw/status-app-protocols.md
+++ b/status/raw/status-app-protocols.md
@@ -28,7 +28,9 @@ Application-level functions are out of scope and specified separately. See:
 - [56/STATUS-COMMUNITIES](../56/communities.md)
 
 ## Status protocol stack
-
+The keywords “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”,
+“SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and
+“OPTIONAL” in this document are to be interpreted as described in [2119](https://www.ietf.org/rfc/rfc2119.txt).
 See the simplified diagram of the Status application protocol stack:
 
 |  |