In The Netherlands and as it turns out at least Norway (contact Martin Grundberg) we have a registry that holds the official address registration for a person. In The Netherlands we have an identified need to mark a Patient address as 'the official address' as opposed to other addresses a person might have.

The Netherlands had created an extension for it, but based on the notion that multiple countries have the same requirement, I have worked with Norway/Martin to generalize its contents and we would like to submit it as a proposal for inclusion in the core extension set.

Our background requirements:

• We need a boolean true = official, false = known not official. We struggled a bit on whether or not we need "official status unknown". We settled for: if you don't know if the address is official, just omit the extension, hence the cardinality of the valueBoolean is 1..1

• It is completely clear from our context which registry is meant, hence we have no identified requirement for inclusion of the name or a pointer to that registry

• It is not relevant in our context 'since when' registration in the registry exists. Secondly you run a risk of being out of sync

The original Dutch version of the extension (STU3) lives here: https://simplifier.net/resolve?canonical=http://fhir.nl/fhir/StructureDefinition/nl-core-address-official

The proposed generalized version (R4, created by hand in absence of Forge support, sorry for incorrections) is attached

We are, I am, open for discussion on requirements that may arise when other countries provide input.