# Feature Definition - FHIR Application Feature Framework Implementation Guide v1.0.0

* [**Table of Contents**](toc.md)
* [**Artifacts Summary**](artifacts.md)
* **Feature Definition**

## Logical Model: Feature Definition 

| | | |
| :--- | :--- | :--- |
| *Official URL*:http://hl7.org/fhir/uv/application-feature/StructureDefinition/FeatureDefinition | *Version*:1.0.0 | |
| * Standards status: *[Trial-use](http://hl7.org/fhir/R5/versions.html#std-process) | [Maturity Level](http://hl7.org/fhir/versions.html#maturity): 2 | *Computable Name*:FeatureDefinition |

 
A definition of a feature that applications may implement, or be required to implement. Features are an aspect of a an applications implementation that generally impacts on the handling of data received from or provided to from the application, which makes it worth declaring. Once declared, 

**Usages:**

* Refer to this Logical Model: [Feature Query Input Parameters](StructureDefinition-FeatureQueryInputParameters.md), [Feature Query Output Parameters](StructureDefinition-FeatureQueryOutputParameters.md) and [Feature](StructureDefinition-feature.md)

You can also check for [usages in the FHIR IG Statistics](https://packages2.fhir.org/xig/resource/hl7.fhir.uv.application-feature|current/StructureDefinition/StructureDefinition-FeatureDefinition.json)

### Formal Views of Profile Content

 [Description of Profiles, Differentials, Snapshots and how the different presentations work](http://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#structure-definitions). 

 

Other representations of profile: [CSV](StructureDefinition-FeatureDefinition.csv), [Excel](StructureDefinition-FeatureDefinition.xlsx) 



## Resource Content

```json
{
  "resourceType" : "StructureDefinition",
  "id" : "FeatureDefinition",
  "extension" : [{
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-implements",
    "valueCanonical" : "http://hl7.org/fhir/StructureDefinition/CanonicalResource"
  },
  {
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
    "valueCode" : "fhir"
  },
  {
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-interface",
    "valueBoolean" : true
  },
  {
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
    "valueInteger" : 2,
    "_valueInteger" : {
      "extension" : [{
        "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
        "valueCanonical" : "http://hl7.org/fhir/uv/application-feature/ImplementationGuide/hl7.fhir.uv.application-feature"
      }]
    }
  },
  {
    "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/application-feature/ImplementationGuide/hl7.fhir.uv.application-feature"
      }]
    }
  }],
  "url" : "http://hl7.org/fhir/uv/application-feature/StructureDefinition/FeatureDefinition",
  "version" : "1.0.0",
  "name" : "FeatureDefinition",
  "title" : "Feature Definition",
  "status" : "active",
  "date" : "2025-12-22T11:42:29-05:00",
  "publisher" : "HL7 International / FHIR Infrastructure",
  "contact" : [{
    "name" : "HL7 International / FHIR Infrastructure",
    "telecom" : [{
      "system" : "url",
      "value" : "http://www.hl7.org/Special/committees/fiwg"
    }]
  }],
  "description" : "A definition of a feature that applications may implement, or be required to implement. Features are an aspect of a an  applications implementation that \ngenerally impacts on the handling of data received from or provided to from the application, which makes it worth declaring. Once declared,  ",
  "jurisdiction" : [{
    "coding" : [{
      "system" : "http://unstats.un.org/unsd/methods/m49/m49.htm",
      "code" : "001",
      "display" : "World"
    }]
  }],
  "fhirVersion" : "5.0.0",
  "mapping" : [{
    "identity" : "w5",
    "uri" : "http://hl7.org/fhir/fivews",
    "name" : "FiveWs Pattern Mapping"
  },
  {
    "identity" : "objimpl",
    "uri" : "http://hl7.org/fhir/object-implementation",
    "name" : "Object Implementation Information"
  },
  {
    "identity" : "rim",
    "uri" : "http://hl7.org/v3",
    "name" : "RIM Mapping"
  }],
  "kind" : "logical",
  "abstract" : false,
  "type" : "http://hl7.org/fhir/uv/application-feature/StructureDefinition/FeatureDefinition",
  "baseDefinition" : "http://hl7.org/fhir/StructureDefinition/DomainResource",
  "derivation" : "specialization",
  "differential" : {
    "element" : [{
      "id" : "FeatureDefinition",
      "path" : "FeatureDefinition",
      "short" : "Feature Definition",
      "definition" : "A definition of a feature that applications may implement, or be required to implement. Features are an aspect of a an  applications implementation that \ngenerally impacts on the handling of data received from or provided to from the application, which makes it worth declaring. Once declared,  "
    },
    {
      "id" : "FeatureDefinition.url",
      "path" : "FeatureDefinition.url",
      "short" : "Canonical identifier for this {{title}}, represented as an absolute URI (globally unique)",
      "definition" : "An absolute URI that is used to identify this {{title}} when it is referenced in a specification, model, design or an instance; also called its canonical identifier. This SHOULD be globally unique and SHOULD be a literal address at which an authoritative instance of this {{title}} is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the {{title}} is stored on different servers.",
      "comment" : "Can be a urn:uuid: or a urn:oid: but real http: addresses are preferred.  Multiple instances may share the same URL if they have a distinct version.\n\nThe determination of when to create a new version of a resource (same url, new version) vs. defining a new artifact is up to the author.  Considerations for making this decision are found in [Technical and Business Versions](http://hl7.org/fhir/R5/resource.html#versions).\n\nIn some cases, the resource can no longer be found at the stated url, but the url itself cannot change. Implementations can use the [meta.source](http://hl7.org/fhir/R5/resource.html#meta) element to indicate where the current master source of the resource can be found.",
      "requirements" : "Allows the {{title}} to be referenced by a single globally unique identifier.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.url",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "uri"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.identifier"
      }]
    },
    {
      "id" : "FeatureDefinition.identifier",
      "path" : "FeatureDefinition.identifier",
      "short" : "Additional identifier for the {{title}}",
      "definition" : "A formal identifier that is used to identify this {{title}} when it is represented in other formats, or referenced in a specification, model, design or an instance.",
      "comment" : "Typically, this is used for identifiers that can go in an HL7 V3 II (instance identifier) data type, and can then identify this {{title}} outside of FHIR, where it is not possible to use the logical URI.",
      "requirements" : "Allows externally provided and/or usable business identifiers to be easily associated with the {{title}}.",
      "min" : 0,
      "max" : "*",
      "base" : {
        "path" : "CanonicalResource.identifier",
        "min" : 0,
        "max" : "*"
      },
      "type" : [{
        "code" : "Identifier"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.identifier"
      },
      {
        "identity" : "objimpl",
        "map" : "no-gen-base"
      }]
    },
    {
      "id" : "FeatureDefinition.version",
      "path" : "FeatureDefinition.version",
      "short" : "Business version of the {{title}}",
      "definition" : "The identifier that is used to identify this version of the {{title}} when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the {{title}} author and is not expected to be globally unique. For example, it might be a timestamp (e.g. yyyymmdd) if a managed version is not available. There is also no expectation that versions can be placed in a lexicographical sequence without additional knowledge.  (See the versionAlgorithm element.)",
      "comment" : "There may be different {{title}}s that have the same url but different versions.  The version can be appended to the url in a reference to allow a reference to a particular business version of the {{title}} with the format [url]|[version]. The version SHOULD NOT contain a '#' - see [Business Version](http://hl7.org/fhir/R5/resource.html#bv-format).",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.version",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.version"
      }]
    },
    {
      "id" : "FeatureDefinition.versionAlgorithm[x]",
      "path" : "FeatureDefinition.versionAlgorithm[x]",
      "short" : "How to compare versions",
      "definition" : "Indicates the mechanism used to compare versions to determine which is more current.",
      "comment" : "If set as a string, this is a FHIRPath expression that has two additional context variables passed in - %version1 and %version2 and will return a negative number if version1 is newer, a positive number if version2 and a 0 if the version ordering can't be successfully be determined.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.versionAlgorithm[x]",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      },
      {
        "code" : "Coding"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "binding" : {
        "strength" : "extensible",
        "valueSet" : "http://hl7.org/fhir/ValueSet/version-algorithm|5.0.0"
      }
    },
    {
      "id" : "FeatureDefinition.name",
      "path" : "FeatureDefinition.name",
      "short" : "Name for this {{title}} (computer friendly)",
      "definition" : "A natural language name identifying the {{title}}. This name should be usable as an identifier for the resource by machine processing applications such as code generation.",
      "comment" : "The name is not expected to be globally unique. The name should be a simple alphanumeric type no-whitespace name to ensure that it is machine-processing friendly.",
      "requirements" : "Supports code generation.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.name",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      }],
      "condition" : ["cnl-0"],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true
    },
    {
      "id" : "FeatureDefinition.title",
      "path" : "FeatureDefinition.title",
      "short" : "Name for this {{title}} (human friendly)",
      "definition" : "A short, descriptive, user-friendly title for the {{title}}.",
      "comment" : "This name does not need to be machine-processing friendly and may contain punctuation, white-space, etc.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.title",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true
    },
    {
      "id" : "FeatureDefinition.status",
      "path" : "FeatureDefinition.status",
      "short" : "draft | active | retired | unknown",
      "definition" : "The current state of this {{title}}.",
      "comment" : "A nominal state-transition diagram can be found in the [Definition pattern](http://hl7.org/fhir/R5/definition.html#statemachine) documentation.\n\nUnknown does not represent 'other' - one of the defined statuses must apply.  Unknown is used when the authoring system is not sure what the current status is.\n\nSee guidance around (not) making local changes to elements [here](http://hl7.org/fhir/R5/canonicalresource.html#localization).",
      "requirements" : "Enables tracking the life-cycle of the content and filtering of {{title}}s that are appropriate for use versus not.",
      "min" : 1,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.status",
        "min" : 1,
        "max" : "1"
      },
      "type" : [{
        "code" : "code"
      }],
      "mustSupport" : false,
      "isModifier" : true,
      "isModifierReason" : "This is labeled as \"Is Modifier\" because applications should not use a retired {{title}} without due consideration",
      "isSummary" : true,
      "binding" : {
        "extension" : [{
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName",
          "valueString" : "PublicationStatus"
        }],
        "strength" : "required",
        "description" : "The lifecycle status of an artifact.",
        "valueSet" : "http://hl7.org/fhir/ValueSet/publication-status|5.0.0"
      },
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.status"
      }]
    },
    {
      "id" : "FeatureDefinition.experimental",
      "path" : "FeatureDefinition.experimental",
      "short" : "For testing purposes, not real usage",
      "definition" : "A Boolean value to indicate that this {{title}} is authored for testing purposes (or education/evaluation/marketing) and is not intended for genuine usage.",
      "comment" : "Allows filtering of {{title}}s that are appropriate for use versus not.",
      "requirements" : "Enables experimental content to be developed following the same lifecycle that would be used for a production-level {{title}}.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.experimental",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "boolean"
      }],
      "meaningWhenMissing" : "If absent, this resource is treated as though it is not experimental.",
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.class"
      }]
    },
    {
      "id" : "FeatureDefinition.date",
      "path" : "FeatureDefinition.date",
      "short" : "Date last changed",
      "definition" : "The date (and optionally time) when the {{title}} was last significantly changed. The date must change when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the {{title}} changes.",
      "comment" : "The date is often not tracked until the resource is published, but may be present on draft content. Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the {{title}}. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.\n\nSee guidance around (not) making local changes to elements [here](http://hl7.org/fhir/R5/canonicalresource.html#localization).",
      "alias" : ["Revision Date"],
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.date",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "dateTime"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.recorded"
      }]
    },
    {
      "id" : "FeatureDefinition.publisher",
      "path" : "FeatureDefinition.publisher",
      "short" : "Name of the publisher/steward (organization or individual)",
      "definition" : "The name of the organization or individual responsible for the release and ongoing maintenance of the {{title}}.",
      "comment" : "Usually an organization but may be an individual. The publisher (or steward) of the {{title}} is the organization or individual primarily responsible for the maintenance and upkeep of the {{title}}. This is not necessarily the same individual or organization that developed and initially authored the content. The publisher is the primary point of contact for questions or issues with the {{title}}. This item SHOULD be populated unless the information is available from context.",
      "requirements" : "Helps establish the \"authority/credibility\" of the {{title}}.  May also allow for contact.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.publisher",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.witness"
      }]
    },
    {
      "id" : "FeatureDefinition.contact",
      "path" : "FeatureDefinition.contact",
      "short" : "Contact details for the publisher",
      "definition" : "Contact details to assist a user in finding and communicating with the publisher.",
      "comment" : "May be a web site, an email address, a telephone number, etc.\n\nSee guidance around (not) making local changes to elements [here](http://hl7.org/fhir/R5/canonicalresource.html#localization).",
      "min" : 0,
      "max" : "*",
      "base" : {
        "path" : "CanonicalResource.contact",
        "min" : 0,
        "max" : "*"
      },
      "type" : [{
        "code" : "ContactDetail"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true
    },
    {
      "id" : "FeatureDefinition.description",
      "path" : "FeatureDefinition.description",
      "short" : "Natural language description of the {{title}}",
      "definition" : "A free text natural language description of the {{title}} from a consumer's perspective.",
      "comment" : "This description can be used to capture details such as comments about misuse, instructions for clinical use and interpretation, literature references, examples from the paper world, etc. It is not a rendering of the {{title}} as conveyed in the 'text' field of the resource itself. This item SHOULD be populated unless the information is available from context.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.description",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "markdown"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : false
    },
    {
      "id" : "FeatureDefinition.useContext",
      "path" : "FeatureDefinition.useContext",
      "short" : "The context that the content is intended to support",
      "definition" : "The content was developed with a focus and intent of supporting the contexts that are listed. These contexts may be general categories (gender, age, ...) or may be references to specific programs (insurance plans, studies, ...) and may be used to assist with indexing and searching for appropriate {{title}}s.",
      "comment" : "When multiple useContexts are specified, there is no expectation that all or even any of the contexts apply.",
      "requirements" : "Assist in searching for appropriate content.",
      "min" : 0,
      "max" : "*",
      "base" : {
        "path" : "CanonicalResource.useContext",
        "min" : 0,
        "max" : "*"
      },
      "type" : [{
        "code" : "UsageContext"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true
    },
    {
      "id" : "FeatureDefinition.jurisdiction",
      "path" : "FeatureDefinition.jurisdiction",
      "short" : "Intended jurisdiction for {{title}} (if applicable)",
      "definition" : "A legal or geographic region in which the {{title}} is intended to be used.",
      "comment" : "It may be possible for the {{title}} to be used in jurisdictions other than those for which it was originally designed or intended.\n\nDEPRECATION NOTE: For consistency, implementations are encouraged to migrate to using the new 'jurisdiction' code in the useContext element.  (I.e. useContext.code indicating http://terminology.hl7.org/CodeSystem/usage-context-type#jurisdiction and useContext.valueCodeableConcept indicating the jurisdiction.)",
      "min" : 0,
      "max" : "*",
      "base" : {
        "path" : "CanonicalResource.jurisdiction",
        "min" : 0,
        "max" : "*"
      },
      "type" : [{
        "code" : "CodeableConcept"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : true,
      "binding" : {
        "extension" : [{
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName",
          "valueString" : "Jurisdiction"
        }],
        "strength" : "extensible",
        "description" : "Countries and regions within which this artifact is targeted for use.",
        "valueSet" : "http://hl7.org/fhir/ValueSet/jurisdiction|5.0.0"
      }
    },
    {
      "id" : "FeatureDefinition.purpose",
      "path" : "FeatureDefinition.purpose",
      "short" : "Why this {{title}} is defined",
      "definition" : "Explanation of why this {{title}} is needed and why it has been designed as it has.",
      "comment" : "This element does not describe the usage of the {{title}}. Instead, it provides traceability of \"why\" the resource is either needed or \"why\" it is defined as it is.  This may be used to point to source materials or specifications that drove the structure of this {{title}}.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.purpose",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "markdown"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : false,
      "mapping" : [{
        "identity" : "w5",
        "map" : "FiveWs.why[x]"
      },
      {
        "identity" : "objimpl",
        "map" : "no-gen-base"
      }]
    },
    {
      "id" : "FeatureDefinition.copyright",
      "path" : "FeatureDefinition.copyright",
      "short" : "Use and/or publishing restrictions",
      "definition" : "A copyright statement relating to the {{title}} and/or its contents. Copyright statements are generally legal restrictions on the use and publishing of the {{title}}.",
      "comment" : "The short copyright declaration (e.g. (c) '2015+ xyz organization' should be sent in the copyrightLabel element.",
      "requirements" : "Consumers must be able to determine any legal restrictions on the use of the {{title}} and/or its content.",
      "alias" : ["License", "Restrictions"],
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.copyright",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "markdown"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : false,
      "mapping" : [{
        "identity" : "objimpl",
        "map" : "no-gen-base"
      }]
    },
    {
      "id" : "FeatureDefinition.copyrightLabel",
      "extension" : [{
        "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-translatable",
        "valueBoolean" : true
      },
      {
        "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-translatable",
        "valueBoolean" : true
      }],
      "path" : "FeatureDefinition.copyrightLabel",
      "short" : "Copyright holder and year(s)",
      "definition" : "A short string (<50 characters), suitable for inclusion in a page footer that identifies the copyright holder, effective period, and optionally whether rights are resctricted. (e.g. 'All rights reserved', 'Some rights reserved').",
      "comment" : "The (c) symbol should NOT be included in this string. It will be added by software when rendering the notation. Full details about licensing, restrictions, warrantees, etc. goes in the more general 'copyright' element.",
      "requirements" : "Defines the content expected to be rendered in all representations of the artifact.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "CanonicalResource.copyrightLabel",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      }],
      "mustSupport" : false,
      "isModifier" : false,
      "isSummary" : false
    },
    {
      "id" : "FeatureDefinition.valueType",
      "path" : "FeatureDefinition.valueType",
      "short" : "Type of value associated with the feature",
      "definition" : "Features are very boolean: true or false for whether the application implements the feature, but the value \nassociated with the feature might be a number, a string, or some kind of code",
      "min" : 1,
      "max" : "1",
      "type" : [{
        "code" : "code"
      }],
      "binding" : {
        "strength" : "required",
        "valueSet" : "http://hl7.org/fhir/ValueSet/data-types"
      }
    },
    {
      "id" : "FeatureDefinition.valueSet",
      "path" : "FeatureDefinition.valueSet",
      "short" : "ValueSet that controls what coded value are allowed",
      "definition" : "If a value set is specified, the value of the data type must come from the value set, and the \nvalue type must be one of the bindeable types defined in the FHIR specification",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "canonical",
        "targetProfile" : ["http://hl7.org/fhir/StructureDefinition/ValueSet"]
      }]
    },
    {
      "id" : "FeatureDefinition.contextDefinition",
      "path" : "FeatureDefinition.contextDefinition",
      "short" : "Human readable documentation describing how to interpret the context fields",
      "definition" : "The contextDefinition provides human readable documentation describing how to interpret the context fields. ",
      "min" : 1,
      "max" : "1",
      "type" : [{
        "code" : "markdown"
      }]
    },
    {
      "id" : "FeatureDefinition.contextExpressionLanguage",
      "path" : "FeatureDefinition.contextExpressionLanguage",
      "short" : "The mime type of context, if context uses an expression language",
      "definition" : "The contextExpressionLanguage specifies the mime type of context, if context uses an expression language.",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "code"
      }],
      "binding" : {
        "strength" : "required",
        "valueSet" : "http://hl7.org/fhir/ValueSet/mimetypes"
      }
    },
    {
      "id" : "FeatureDefinition.context",
      "path" : "FeatureDefinition.context",
      "short" : "The context(s) on which this feature can be defined",
      "definition" : "The context(s) on which this feature can be defined. This is used to state where the feature applies. some\nfeatures are defined on applications, but others apply to particular resources, or operations on resources, or particular\ncode systems etc",
      "min" : 0,
      "max" : "*",
      "type" : [{
        "code" : "string"
      }]
    },
    {
      "id" : "FeatureDefinition.qualifier",
      "path" : "FeatureDefinition.qualifier",
      "short" : "A qualifier that might provided more information about a feature implementation",
      "definition" : "A qualifier is an extra piece of information that MAY or SHALL be provided when the feature is described/specified \nthat provides additional information about the feature. E.g. a feature defined on a resource may only be applicable \nto particular events associated with the resource, or ...?",
      "min" : 0,
      "max" : "*",
      "type" : [{
        "code" : "BackboneElement"
      }]
    },
    {
      "id" : "FeatureDefinition.qualifier.name",
      "path" : "FeatureDefinition.qualifier.name",
      "short" : "The name of the feature",
      "definition" : "The name of the feature",
      "min" : 1,
      "max" : "1",
      "type" : [{
        "code" : "code"
      }]
    },
    {
      "id" : "FeatureDefinition.qualifier.description",
      "path" : "FeatureDefinition.qualifier.description",
      "short" : "A human-readable description of the qualifier.",
      "definition" : "A human-readable description of the qualifier.",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "string"
      }]
    },
    {
      "id" : "FeatureDefinition.qualifier.valueType",
      "path" : "FeatureDefinition.qualifier.valueType",
      "short" : "Type of value associated with the feature",
      "definition" : "Features are very boolean: true or false for whether the application implements the feature, but the value \nassociated with the feature might be a number, a string, or some kind of code",
      "min" : 1,
      "max" : "1",
      "type" : [{
        "code" : "code"
      }],
      "binding" : {
        "strength" : "required",
        "valueSet" : "http://hl7.org/fhir/ValueSet/data-types"
      }
    },
    {
      "id" : "FeatureDefinition.qualifier.optional",
      "path" : "FeatureDefinition.qualifier.optional",
      "short" : "Whether the feature is optional, or must always be present",
      "definition" : "Whether the feature is optional, or must always be present when a feature is referred to ",
      "min" : 1,
      "max" : "1",
      "type" : [{
        "code" : "boolean"
      }]
    }]
  }
}

```
