R4 Ballot #1 (Mixed Normative/Trial use) Current Build
This is the FHIR R4 Mixed Normative/Trial Use Ballot #1, and the version for the Cologne Connectathon in May 2018. The current version is R3 . See the ballot introduction for details about the ballot. For a full list of available versions, see the Directory of published versions and Timelines for an explanation of STU and other statuses.
FHIR Infrastructure Work Group Maturity Level : 5 Normative Ballot Standards Status : Normative
Normative Candidate Note: This page is candidate normative content for R4 in the Infrastructure Package . Once normative, it will lose it's Maturity Level, and breaking changes will no longer be made. null
Element BackboneElement
Standards Status This element has a standards status of "Normative" which is different to the status of the whole resource
Definition

Base definition for all elements in a resource. Control 1..1 Invariants Defined on this element ele-1 : All FHIR elements must have a @value or children ( expression : hasValue() | (children().count() > id.count()), xpath: @value|f:*|h:div) Affect this element Element.id Definition Unique id for the element within that are defined inside a resource (for internal references). This may be any string value that does - but not contain spaces. those in a data type.

Control Cardinality 0..1 0..*
Type string Element
Element.extension BackboneElement.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element. element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Control Cardinality 0..*
Type Extension
Is Modifier true (Reason: Modifier extensions are expected to modify the meaning or interpretation of the element that contains them)
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions .

Alternate Names extensions; user content content; modifiers
Summary true
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.