2. Requirements Language

This section preserves the RFC text for optimistic HTTP/1.1 protocol transitions, including request smuggling risks, parser exploit risks, existing Upgrade tokens, HTTP CONNECT requirements, and IANA status.

2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.