The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", "MAY", "RECOMMENDED", "OPTIONAL", and "REQUIRED" in this document are to be interpreted as described in RFC 2119. 1
+The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", "MAY", "RECOMMENDED", "OPTIONAL", and "REQUIRED" in this document are to be interpreted as described in BCP 14 1 when, and only when, they appear in all capitals.
The term "network upgrade" in this document is to be interpreted as described in ZIP 200. 3