ConformanceExpectation

Indicates the degree of adherence to a specified behavior or capability expected in order for a system to be deemed conformant with a specification.

This value set has an inline code system http://hl7.org/fhir/conformance-expectation, which defines the following codes:

Code	Display	Definition
SHALL	SHALL	Support for the specified capability is required to be considered conformant.
SHOULD	SHOULD	Support for the specified capability is strongly encouraged and failure to support it should only occur after careful consideration.
MAY	MAY	Support for the specified capability is not necessary to be considered conformant and the requirement should be considered strictly optional.
SHOULD-NOT	SHOULD-NOT	Support for the specified capability is strongly discouraged and should occur only after careful consideration.