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Narrative

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Generated Narrative: StructureDefinition ext-R2-Conformance.acceptUnknown

Name	Flags	Card.	Type	Description & Constraints
Extension		1..1	Extension(4.3.0)	DSTU2: no | extensions | elements | both (new)
url		1..1	uri	"http://hl7.org/fhir/1.0/StructureDefinition/extension-Conformance.acceptUnknown"
value[x]		1..1	code	no | extensions | elements | both Binding: R2UnknownContentCodeForR4B (0.1.0) (required): A code that indicates whether an application accepts unknown elements or extensions when reading resources.
Documentation for this format

Source1

{
  "resourceType": "StructureDefinition",
  "id": "ext-R2-Conformance.acceptUnknown",
  "text": {
    "status": "extensions",
    "div": "<!-- snip (see above) -->"
  },
  "extension": [
    {
      "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
      "valueCode": "fhir"
    },
    {
      "extension": [
        {
          "url": "packageId",
          "valueId": "hl7.fhir.uv.xver-r2.r4b"
        },
        {
          "url": "version",
          "valueString": "0.1.0"
        },
        {
          "url": "uri",
          "valueUri": "http://hl7.org/fhir/uv/xver/ImplementationGuide/hl7.fhir.uv.xver-r2.r4b"
        }
      ],
      "url": "http://hl7.org/fhir/StructureDefinition/package-source"
    },
    {
      "extension": [
        {
          "url": "startFhirVersion",
          "valueCode": "4.3"
        },
        {
          "url": "endFhirVersion",
          "valueCode": "4.3"
        }
      ],
      "url": "http://hl7.org/fhir/StructureDefinition/version-specific-use"
    },
    {
      "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
      "valueInteger": 0,
      "_valueInteger": {
        "extension": [
          {
            "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
            "valueCanonical": "http://hl7.org/fhir/uv/xver/ImplementationGuide/hl7.fhir.uv.xver-r2.r4b"
          }
        ]
      }
    },
    {
      "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
      "valueCode": "trial-use",
      "_valueCode": {
        "extension": [
          {
            "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
            "valueCanonical": "http://hl7.org/fhir/uv/xver/ImplementationGuide/hl7.fhir.uv.xver-r2.r4b"
          }
        ]
      }
    }
  ],
  "url": "http://hl7.org/fhir/1.0/StructureDefinition/extension-Conformance.acceptUnknown",
  "version": "0.1.0",
  "name": "ExtensionConformance_AcceptUnknown",
  "title": "DSTU2: no | extensions | elements | both (new)",
  "status": "active",
  "experimental": false,
  "date": "2026-03-17T21:02:03.8104715+00:00",
  "publisher": "FHIR Infrastructure",
  "contact": [
    {
      "name": "FHIR Infrastructure",
      "telecom": [
        {
          "system": "url",
          "value": "http://www.hl7.org/Special/committees/fiwg"
        }
      ]
    }
  ],
  "description": "DSTU2: `Conformance.acceptUnknown` (new:code)",
  "jurisdiction": [
    {
      "coding": [
        {
          "system": "http://unstats.un.org/unsd/methods/m49/m49.htm",
          "code": "001",
          "display": "World"
        }
      ]
    }
  ],
  "purpose": "This extension is part of the cross-version definitions generated to enable use of the\r\nelement `Conformance.acceptUnknown` as defined in FHIR DSTU2\r\nin FHIR R4B.\r\n\r\nThe source element is defined as:\r\n`Conformance.acceptUnknown` 1..1 `code`\r\n\r\nAcross FHIR versions, the element set has been mapped as:\r\n*  DSTU2: `Conformance.acceptUnknown` 1..1 `code`\n*  STU3: `CapabilityStatement.acceptUnknown` 1..1 `code`\r\n\r\nFollowing are the generation technical comments:\r\nElement `Conformance.acceptUnknown` has a context of CapabilityStatement based on following the parent source element upwards and mapping to `CapabilityStatement`.\nElement `Conformance.acceptUnknown` has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element).",
  "fhirVersion": "4.3.0",
  "mapping": [
    {
      "identity": "rim",
      "uri": "http://hl7.org/v3",
      "name": "RIM Mapping"
    }
  ],
  "kind": "complex-type",
  "abstract": false,
  "context": [
    {
      "type": "element",
      "expression": "CapabilityStatement"
    }
  ],
  "type": "Extension",
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension|4.3.0",
  "derivation": "constraint",
  "snapshot": {
    "extension": [
      {
        "url": "http://hl7.org/fhir/tools/StructureDefinition/snapshot-base-version",
        "valueString": "4.3.0"
      }
    ],
    "element": [
      {
        "id": "Extension",
        "path": "Extension",
        "short": "DSTU2: no | extensions | elements | both (new)",
        "definition": "DSTU2: `Conformance.acceptUnknown` (new:code)",
        "comment": "Element `Conformance.acceptUnknown` has a context of CapabilityStatement based on following the parent source element upwards and mapping to `CapabilityStatement`.\nElement `Conformance.acceptUnknown` has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element).\nUnknown elements in a resource can only arise as later versions of the specification are published, because this is the only place where such elements can be defined. Hence accepting unknown elements is about inter-version compatibility.  Applications are recommended to accept unknown extensions and elements ('both'), but this is not always possible.",
        "min": 1,
        "max": "1",
        "base": {
          "path": "Extension",
          "min": 0,
          "max": "*"
        },
        "condition": [
          "ele-1"
        ],
        "constraint": [
          {
            "key": "ele-1",
            "severity": "error",
            "human": "All FHIR elements must have a @value or children unless an empty Parameters resource",
            "expression": "hasValue() or (children().count() > id.count()) or $this is Parameters",
            "xpath": "@value|f:*|h:div|self::f:Parameters",
            "source": "http://hl7.org/fhir/StructureDefinition/Element|4.3.0"
          },
          {
            "key": "ext-1",
            "severity": "error",
            "human": "Must have either extensions or value[x], not both",
            "expression": "extension.exists() != value.exists()",
            "xpath": "exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')])",
            "source": "http://hl7.org/fhir/StructureDefinition/Extension|4.3.0"
          }
        ],
        "isModifier": false
      },
      {
        "id": "Extension.id",
        "path": "Extension.id",
        "representation": [
          "xmlAttr"
        ],
        "short": "Unique id for inter-element referencing",
        "definition": "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.",
        "min": 0,
        "max": "1",
        "base": {
          "path": "Element.id",
          "min": 0,
          "max": "1"
        },
        "type": [
          {
            "extension": [
              {
                "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
                "valueUrl": "id"
              }
            ],
            "code": "http://hl7.org/fhirpath/System.String"
          }
        ],
        "isModifier": false,
        "isSummary": false,
        "mapping": [
          {
            "identity": "rim",
            "map": "n/a"
          }
        ]
      },
      {
        "id": "Extension.extension",
        "path": "Extension.extension",
        "slicing": {
          "discriminator": [
            {
              "type": "value",
              "path": "url"
            }
          ],
          "description": "Extensions are always sliced by (at least) url",
          "rules": "open"
        },
        "short": "Additional content defined by implementations",
        "definition": "May be used to represent additional information that is not part of the basic definition of the element. 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.",
        "comment": "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.",
        "alias": [
          "extensions",
          "user content"
        ],
        "min": 0,
        "max": "*",
        "base": {
          "path": "Element.extension",
          "min": 0,
          "max": "*"
        },
        "type": [
          {
            "code": "Extension"
          }
        ],
        "constraint": [
          {
            "key": "ele-1",
            "severity": "error",
            "human": "All FHIR elements must have a @value or children",
            "expression": "hasValue() or (children().count() > id.count())",
            "xpath": "@value|f:*|h:div",
            "source": "http://hl7.org/fhir/StructureDefinition/Element|4.3.0"
          },
          {
            "key": "ext-1",
            "severity": "error",
            "human": "Must have either extensions or value[x], not both",
            "expression": "extension.exists() != value.exists()",
            "xpath": "exists(f:extension)!=exists(f:*[starts-with(local-name(.), \"value\")])",
            "source": "http://hl7.org/fhir/StructureDefinition/Extension|4.3.0"
          }
        ],
        "isModifier": false,
        "isSummary": false,
        "mapping": [
          {
            "identity": "rim",
            "map": "n/a"
          }
        ]
      },
      {
        "id": "Extension.url",
        "path": "Extension.url",
        "representation": [
          "xmlAttr"
        ],
        "short": "identifies the meaning of the extension",
        "definition": "Source of the definition for the extension code - a logical name or a URL.",
        "comment": "The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.",
        "min": 1,
        "max": "1",
        "base": {
          "path": "Extension.url",
          "min": 1,
          "max": "1"
        },
        "type": [
          {
            "extension": [
              {
                "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
                "valueUrl": "uri"
              }
            ],
            "code": "http://hl7.org/fhirpath/System.String"
          }
        ],
        "fixedUri": "http://hl7.org/fhir/1.0/StructureDefinition/extension-Conformance.acceptUnknown",
        "isModifier": false,
        "isSummary": false,
        "mapping": [
          {
            "identity": "rim",
            "map": "N/A"
          }
        ]
      },
      {
        "id": "Extension.value[x]",
        "path": "Extension.value[x]",
        "short": "no | extensions | elements | both",
        "definition": "A code that indicates whether the application accepts unknown elements or extensions when reading resources.",
        "comment": "Unknown elements in a resource can only arise as later versions of the specification are published, because this is the only place where such elements can be defined. Hence accepting unknown elements is about inter-version compatibility.  Applications are recommended to accept unknown extensions and elements ('both'), but this is not always possible.",
        "min": 1,
        "max": "1",
        "base": {
          "path": "Extension.value[x]",
          "min": 0,
          "max": "1"
        },
        "type": [
          {
            "code": "code"
          }
        ],
        "constraint": [
          {
            "key": "ele-1",
            "severity": "error",
            "human": "All FHIR elements must have a @value or children",
            "expression": "hasValue() or (children().count() > id.count())",
            "xpath": "@value|f:*|h:div",
            "source": "http://hl7.org/fhir/StructureDefinition/Element|4.3.0"
          }
        ],
        "isModifier": false,
        "isSummary": false,
        "binding": {
          "strength": "required",
          "description": "A code that indicates whether an application accepts unknown elements or extensions when reading resources.",
          "valueSet": "http://hl7.org/fhir/uv/xver/ValueSet/R2-unknown-content-code-for-R4B|0.1.0"
        },
        "mapping": [
          {
            "identity": "rim",
            "map": "N/A"
          }
        ]
      }
    ]
  },
  "differential": {
    "element": [
      {
        "id": "Extension",
        "path": "Extension",
        "short": "DSTU2: no | extensions | elements | both (new)",
        "definition": "DSTU2: `Conformance.acceptUnknown` (new:code)",
        "comment": "Element `Conformance.acceptUnknown` has a context of CapabilityStatement based on following the parent source element upwards and mapping to `CapabilityStatement`.\nElement `Conformance.acceptUnknown` has no mapping targets in FHIR R4B. Typically, this is because the element has been added (is a new element).\nUnknown elements in a resource can only arise as later versions of the specification are published, because this is the only place where such elements can be defined. Hence accepting unknown elements is about inter-version compatibility.  Applications are recommended to accept unknown extensions and elements ('both'), but this is not always possible.",
        "min": 1,
        "max": "1",
        "base": {
          "path": "Extension",
          "min": 0,
          "max": "*"
        },
        "isModifier": false
      },
      {
        "id": "Extension.url",
        "path": "Extension.url",
        "min": 1,
        "max": "1",
        "base": {
          "path": "Extension.url",
          "min": 1,
          "max": "1"
        },
        "fixedUri": "http://hl7.org/fhir/1.0/StructureDefinition/extension-Conformance.acceptUnknown"
      },
      {
        "id": "Extension.value[x]",
        "path": "Extension.value[x]",
        "short": "no | extensions | elements | both",
        "definition": "A code that indicates whether the application accepts unknown elements or extensions when reading resources.",
        "comment": "Unknown elements in a resource can only arise as later versions of the specification are published, because this is the only place where such elements can be defined. Hence accepting unknown elements is about inter-version compatibility.  Applications are recommended to accept unknown extensions and elements ('both'), but this is not always possible.",
        "min": 1,
        "max": "1",
        "base": {
          "path": "Extension.value[x]",
          "min": 0,
          "max": "1"
        },
        "type": [
          {
            "code": "code"
          }
        ],
        "binding": {
          "strength": "required",
          "description": "A code that indicates whether an application accepts unknown elements or extensions when reading resources.",
          "valueSet": "http://hl7.org/fhir/uv/xver/ValueSet/R2-unknown-content-code-for-R4B|0.1.0"
        }
      }
    ]
  }
}