We need to consider the compatibility rules for taking artifacts to normative when they contain content that is based on and dependent on decisions that are made by an external organization, over which we have no control. How does this affect the understanding of not having breaking changes for normative artifacts? In these cases updates to the content from decisions made by an external organization may break existing implementations that are using that content.

An example of this is the terminology guidance in the "Using XXX with FHIR" pages. The "Using SNOMED CT with FHIR" page is currently maturity level 5 and may be a candidate for normative in a future release (it is not marked for that in R4). As SNOMED International updates their content (including deprecating codes) or potentially makes changes to the concept model or reference set contents and structures or the URI specification (as some examples) this could break the existing terminology service provider and consumer implementations.