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When you are developing an implementation, make sure that you have a clear understanding of the specification of the protocol and the artefact. The specification is meant to be precise enough to ensure that your implementation is interoperable with others or is at least very close to be. In case of questions or unclarities, do not consciously make assumptions but contact the author of the specification. Interoperability is primarily a matter of correct and consensual interpretation of this specification. Assumptions made that are not shared amongst the community of implementers will imped impede a proper implementation and will require adaptations in a later stage in the software development lifecycle, with a higher cost.
Take into account Consider that the intended audience of the specification is wide. Knowing that product managers, end-users, test developers or product developers not always fully share the author’s background and expertise, be aware that interpretation mistakes or liberties will abound.
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The optional character of a specified feature, when concerning an artifact that may be produced and consumed, is a common source of confusion and interoperability failure. An artifact MAY implement a feature. This clearly means that a compliant device producing such an artifact MAY omit this feature. However, any compliant device consuming such an artifact MUST be able to process this feature, should it be present (unless specified otherwise). In this way, useful or important information included in the optional feature, is not omitted by the consuming application.