Optional is useful in a requirements RFC. Feature x is REQUIRED Feature y is OPTIONAL - Stewart On 11/08/2016 12:27, Dearlove, Christopher (UK) wrote:
Grammatically, RECOMMENDED is sometimes useful, as using SHOULD instead can produce less clear sentences. In principal the same applies to OPTIONAL, but I've never had cause to use it. I wouldn't miss SHALL. Except that SHALL is often the word used outside the IETF rather than must, and there may be many RFCs using it, so do need to keep the explanation, even if deprecated to use it in new documents.