Subscriptions R5 Backport
1.2.0-ballot - ballot

Subscriptions R5 Backport, published by HL7 International / FHIR Infrastructure. This guide is not an authorized publication; it is the continuous build for version 1.2.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/fhir-subscription-backport-ig/ and changes regularly. See the Directory of published versions

## Resource Profile: BackportSubscription - Detailed Descriptions

Page standards status: Trial-use

Definitions for the backport-subscription resource profile.

- Differential Elements Table
- Key Elements Table
- Snapshot Elements Table

Guidance on how to interpret the contents of this table can be found here

0. Subscription
2. Subscription.extension
Slicing | This element introduces a set of slices on `Subscription.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
4. Subscription.extension:identifier
Slice Name | identifier
Control | 0..*
Type | Extension(Extension Definition for Subscription.identifier for Version 5.0) (Extension Type: Identifier)
6. Subscription.criteria
Definition | When using topic-based subscriptions, the primary criteria is always the topic, indicated by its canonical URL.
Short | Canonical URL for the topic used to generate events
Must Support | true
8. Subscription.criteria.extension
Slicing | This element introduces a set of slices on `Subscription.criteria.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
10. Subscription.criteria.extension:filterCriteria
Slice Name | filterCriteria
Definition | Search-style filters to be applied to narrow the subscription topic stream. Keys can be either search parameters appropriate to the filtering resource or keys defined within the subscription topic.
Short | Filtering critiera applied to events
Comments | When multiple filters are applied, evaluates to true if all the conditions are met; otherwise it returns false. (i.e., logical AND).
Control | 0..*
Type | Extension(Backported R5 FilterBy Criteria) (Extension Type: string)
Must Support | true
Summary | true
12. Subscription.channel
14. Subscription.channel.extension
Slicing | This element introduces a set of slices on `Subscription.channel.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
16. Subscription.channel.extension:heartbeatPeriod
Slice Name | heartbeatPeriod
Definition | If present, a 'hearbeat' notification (keepalive) is sent via this channel with an the interval period equal to this elements integer value in seconds. If not present, a heartbeat notification is not sent.
Short | Interval in seconds to send 'heartbeat' notification
Control | 0..1
Type | Extension(Backport R5 Subscription Heartbeat Period) (Extension Type: unsignedInt)
18. Subscription.channel.extension:timeout
Slice Name | timeout
Definition | If present, the maximum amount of time a server will allow before failing a notification attempt.
Short | Timeout in seconds to attempt notification delivery
Control | 0..1
Type | Extension(Backport R5 Subscription Timeout) (Extension Type: unsignedInt)
20. Subscription.channel.extension:maxCount
Slice Name | maxCount
Definition | If present, the maximum number of triggering resources that will be included in a notification bundle (e.g., a server will not include more than this number of trigger resources in a single notification). Note that this is not a strict limit on the number of entries in a bundle, as dependent resources can be included.
Short | Maximum number of triggering resources included in notification bundles
Control | 0..1
Type | Extension(Backported R5 Subscription MaxCount) (Extension Type: positiveInt)
22. Subscription.channel.type
24. Subscription.channel.type.extension
Slicing | This element introduces a set of slices on `Subscription.channel.type.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
26. Subscription.channel.type.extension:customChannelType
Slice Name | customChannelType
Definition | The type of channel to send notifications on.
Short | Extended channel type for notifications
Comments | This extension allows for the use of additional channel types that were not defined in the FHIR R4 subscription definition.
Control | 0..1
Type | Extension(Backported R5 Additional Channel Types) (Extension Type: Coding)
Must Support | true
Summary | true
28. Subscription.channel.payload
Control | 1..?
30. Subscription.channel.payload.extension
Control | 1..?
Slicing | This element introduces a set of slices on `Subscription.channel.payload.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
32. Subscription.channel.payload.extension:content
Slice Name | content
Definition | How much of the resource content to deliver in the notification payload. The choices are an empty payload, only the resource id, or the full resource content.
Short | Notification content level
Comments | Sending the payload has obvious security implications. The server is responsible for ensuring that the content is appropriately secured.
Control | 1..1
Type | Extension(Backport R5 Subscription Payload Content Information) (Extension Type: code)
Must Support | true
Summary | true

Guidance on how to interpret the contents of this table can be found here

0. Subscription
Definition | The subscription resource is used to define a push-based subscription from a server to another system. Once a subscription is registered with the server, the server checks every resource that is created or updated, and if the resource matches the given criteria, it sends a message on the defined "channel" so that another system can take an appropriate action.
Short | Server push subscription criteria
Control | 0..*
Is Modifier | false
Must Support | false
Summary | false
Alternate Names | WebHook, Hook, Routing Rule
Invariants | dom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty()) dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where(((id.exists() and ('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url)))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(uri) = '#').exists()).not()).trace('unmatched', id).empty()) dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty()) dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty()) dom-6: A resource should have narrative for robust management (text.`div`.exists())
2. Subscription.implicitRules
Definition | A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.
Short | A set of rules under which this content was created
Comments | Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.
Control | 0..1
Type | uri
Is Modifier | true because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
4. Subscription.extension
Definition | An Extension May be used to represent additional information that is not part of the basic definition of the resource. 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.
Short | ExtensionAdditional content defined by implementations
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.
Control | 0..*
Type | Extension
Is Modifier | false
Must Support | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
Slicing | This element introduces a set of slices on `Subscription.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
6. Subscription.extension:identifier
Slice Name | identifier
Definition | Optional Extension Element - found in all resources.
Short | Optional Extensions Element
Control | 0..* This element is affected by the following invariants: ele-1
Type | Extension(Extension Definition for Subscription.identifier for Version 5.0) (Extension Type: Identifier)
Is Modifier | false
Must Support | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
8. Subscription.modifierExtension
Definition | May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it 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 is allowed to 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).
Short | Extensions that cannot be ignored
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.
Control | 0..*
Type | Extension
Is Modifier | true because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
Must Support | false
Summary | false
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
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
10. Subscription.status
Definition | The status of the subscription, which marks the server state for managing the subscription.
Short | requested | active | error | off
Comments | A client can only submit subscription resources in the requested or off state. Only the server can move a subscription from requested to active, and then to error. Either the server or the client can turn a subscription off. This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.
Control | 1..1
Binding | The codes SHALL be taken from SubscriptionStatusCodes http://hl7.org/fhir/ValueSet/subscription-status|4.3.0 (required to `http://hl7.org/fhir/ValueSet/subscription-status|4.3.0` ) The status of a subscription.
Type | code
Is Modifier | true because This element is labelled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
12. Subscription.reason
Definition | A description of why this subscription is defined.
Short | Description of why this subscription was created
Control | 1..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
14. Subscription.criteria
Definition | When using topic-based subscriptions, the primary criteria is always the topic, indicated by its canonical URL. The rules that the server should use to determine when to generate notifications for this subscription.
Short | Canonical URL for the topic used to generate eventsRule for server push
Comments | The rules are search criteria (without the [base] part). Like Bundle.entry.request.url, it has no leading "/".
Control | 1..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
16. Subscription.criteria.extension
Definition | An Extension 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.
Short | ExtensionAdditional content defined by implementations
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.
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
Slicing | This element introduces a set of slices on `Subscription.criteria.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
18. Subscription.criteria.extension:filterCriteria
Slice Name | filterCriteria
Definition | Search-style filters to be applied to narrow the subscription topic stream. Keys can be either search parameters appropriate to the filtering resource or keys defined within the subscription topic.
Short | Filtering critiera applied to events
Comments | When multiple filters are applied, evaluates to true if all the conditions are met; otherwise it returns false. (i.e., logical AND).
Control | 0..* This element is affected by the following invariants: ele-1
Type | Extension(Backported R5 FilterBy Criteria) (Extension Type: string)
Is Modifier | false
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
20. Subscription.channel
Definition | Details where to send notifications when resources are received that meet the criteria.
Short | The channel on which to report matches to the criteria
Control | 1..1
Type | BackboneElement
Is Modifier | false
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (hasValue() or (children().count() > id.count()) or $this is Parameters)
22. Subscription.channel.extension
Definition | An Extension 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.
Short | ExtensionAdditional content defined by implementations
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.
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
Slicing | This element introduces a set of slices on `Subscription.channel.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
24. Subscription.channel.extension:heartbeatPeriod
Slice Name | heartbeatPeriod
Definition | If present, a 'hearbeat' notification (keepalive) is sent via this channel with an the interval period equal to this elements integer value in seconds. If not present, a heartbeat notification is not sent.
Short | Interval in seconds to send 'heartbeat' notification
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backport R5 Subscription Heartbeat Period) (Extension Type: unsignedInt)
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
26. Subscription.channel.extension:timeout
Slice Name | timeout
Definition | If present, the maximum amount of time a server will allow before failing a notification attempt.
Short | Timeout in seconds to attempt notification delivery
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backport R5 Subscription Timeout) (Extension Type: unsignedInt)
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
28. Subscription.channel.extension:maxCount
Slice Name | maxCount
Definition | If present, the maximum number of triggering resources that will be included in a notification bundle (e.g., a server will not include more than this number of trigger resources in a single notification). Note that this is not a strict limit on the number of entries in a bundle, as dependent resources can be included.
Short | Maximum number of triggering resources included in notification bundles
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backported R5 Subscription MaxCount) (Extension Type: positiveInt)
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
30. Subscription.channel.modifierExtension
Definition | May be used to represent additional information that is not part of the basic definition of the 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).
Short | Extensions that cannot be ignored even if unrecognized
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.
Control | 0..*
Type | Extension
Is Modifier | true because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
Summary | true
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, modifiers
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
32. Subscription.channel.type
Definition | The type of channel to send notifications on.
Short | rest-hook | websocket | email | sms | message
Control | 1..1
Binding | The codes SHALL be taken from SubscriptionChannelType http://hl7.org/fhir/ValueSet/subscription-channel-type|4.3.0 (required to `http://hl7.org/fhir/ValueSet/subscription-channel-type|4.3.0` ) The type of method used to execute a subscription.
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
34. Subscription.channel.type.extension
Definition | An Extension 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.
Short | ExtensionAdditional content defined by implementations
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.
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
Slicing | This element introduces a set of slices on `Subscription.channel.type.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
36. Subscription.channel.type.extension:customChannelType
Slice Name | customChannelType
Definition | The type of channel to send notifications on.
Short | Extended channel type for notifications
Comments | This extension allows for the use of additional channel types that were not defined in the FHIR R4 subscription definition.
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backported R5 Additional Channel Types) (Extension Type: Coding)
Is Modifier | false
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
38. Subscription.channel.payload
Definition | The mime type to send the payload in - either application/fhir+xml, or application/fhir+json. If the payload is not present, then there is no payload in the notification, just a notification. The mime type "text/plain" may also be used for Email and SMS subscriptions.
Short | MIME type to send, or omit for no payload
Comments | Sending the payload has obvious security implications. The server is responsible for ensuring that the content is appropriately secured.
Control | 10..1
Binding | The codes SHALL be taken from Mime Types http://hl7.org/fhir/ValueSet/mimetypes|4.3.0 (required to `http://hl7.org/fhir/ValueSet/mimetypes|4.3.0` ) BCP 13 (RFCs 2045, 2046, 2047, 4288, 4289 and 2049)
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
40. Subscription.channel.payload.extension
Definition | An Extension 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.
Short | ExtensionAdditional content defined by implementations
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.
Control | 10..*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
Slicing | This element introduces a set of slices on `Subscription.channel.payload.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
42. Subscription.channel.payload.extension:content
Slice Name | content
Definition | How much of the resource content to deliver in the notification payload. The choices are an empty payload, only the resource id, or the full resource content.
Short | Notification content level
Comments | Sending the payload has obvious security implications. The server is responsible for ensuring that the content is appropriately secured.
Control | 1..1 This element is affected by the following invariants: ele-1
Type | Extension(Backport R5 Subscription Payload Content Information) (Extension Type: code)
Is Modifier | false
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`) ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())

Guidance on how to interpret the contents of this table can be found here

0. Subscription
Definition | The subscription resource is used to define a push-based subscription from a server to another system. Once a subscription is registered with the server, the server checks every resource that is created or updated, and if the resource matches the given criteria, it sends a message on the defined "channel" so that another system can take an appropriate action.
Short | Server push subscription criteria
Control | 0..*
Is Modifier | false
Must Support | false
Summary | false
Alternate Names | WebHook, Hook, Routing Rule
Invariants | dom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (`contained.contained.empty()`) dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (`contained.where(((id.exists() and ('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url)))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(uri) = '#').exists()).not()).trace('unmatched', id).empty()`) dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (`contained.meta.versionId.empty() and contained.meta.lastUpdated.empty()`) dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (`contained.meta.security.empty()`) dom-6: A resource should have narrative for robust management (`text.`div`.exists()`)
2. Subscription.id
Definition | The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.
Short | Logical id of this artifact
Comments | The only time that a resource does not have an id is when it is being submitted to the server using a create operation.
Control | 0..1
Type | id
Is Modifier | false
Must Support | false
Summary | true
4. Subscription.meta
Definition | The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.
Short | Metadata about the resource
Control | 0..1
Type | Meta
Is Modifier | false
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
6. Subscription.implicitRules
Definition | A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.
Short | A set of rules under which this content was created
Comments | Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.
Control | 0..1
Type | uri
Is Modifier | true because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
8. Subscription.language
Definition | The base language in which the resource is written.
Short | Language of the resource content
Comments | Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).
Control | 0..1
Binding | The codes SHOULD be taken from CommonLanguages (preferred to `http://hl7.org/fhir/ValueSet/languages` ) IETF language tag
Additional Bindings | Purpose
AllLanguages | Max Binding
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
10. Subscription.text
Definition | A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.
Short | Text summary of the resource, for human interpretation
Comments | Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.
Control | 0..1
Type | Narrative
Is Modifier | false
Must Support | false
Summary | false
Alternate Names | narrative, html, xhtml, display
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
12. Subscription.contained
Definition | These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.
Short | Contained, inline Resources
Comments | This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.
Control | 0..*
Type | Resource
Is Modifier | false
Must Support | false
Summary | false
Alternate Names | inline resources, anonymous resources, contained resources
Invariants | dom-r4b: Containing new R4B resources within R4 resources may cause interoperability issues if instances are shared with R4 systems (`($this is Citation or $this is Evidence or $this is EvidenceReport or $this is EvidenceVariable or $this is MedicinalProductDefinition or $this is PackagedProductDefinition or $this is AdministrableProductDefinition or $this is Ingredient or $this is ClinicalUseDefinition or $this is RegulatedAuthorization or $this is SubstanceDefinition or $this is SubscriptionStatus or $this is SubscriptionTopic) implies (%resource is Citation or %resource is Evidence or %resource is EvidenceReport or %resource is EvidenceVariable or %resource is MedicinalProductDefinition or %resource is PackagedProductDefinition or %resource is AdministrableProductDefinition or %resource is Ingredient or %resource is ClinicalUseDefinition or %resource is RegulatedAuthorization or %resource is SubstanceDefinition or %resource is SubscriptionStatus or %resource is SubscriptionTopic)`)
14. Subscription.extension
Definition | An Extension
Short | Extension
Control | 0..*
Type | Extension
Is Modifier | false
Must Support | false
Summary | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `Subscription.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
16. Subscription.extension:identifier
Slice Name | identifier
Definition | Optional Extension Element - found in all resources.
Short | Optional Extensions Element
Control | 0..* This element is affected by the following invariants: ele-1
Type | Extension(Extension Definition for Subscription.identifier for Version 5.0) (Extension Type: Identifier)
Is Modifier | false
Must Support | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
18. Subscription.modifierExtension
Definition | May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it 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 is allowed to 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).
Short | Extensions that cannot be ignored
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.
Control | 0..*
Type | Extension
Is Modifier | true because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
Must Support | false
Summary | false
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
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
20. Subscription.status
Definition | The status of the subscription, which marks the server state for managing the subscription.
Short | requested | active | error | off
Comments | A client can only submit subscription resources in the requested or off state. Only the server can move a subscription from requested to active, and then to error. Either the server or the client can turn a subscription off. This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.
Control | 1..1
Binding | The codes SHALL be taken from SubscriptionStatusCodes (required to `http://hl7.org/fhir/ValueSet/subscription-status|4.3.0` ) The status of a subscription.
Type | code
Is Modifier | true because This element is labelled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
22. Subscription.contact
Definition | Contact details for a human to contact about the subscription. The primary use of this for system administrator troubleshooting.
Short | Contact details for source (e.g. troubleshooting)
Control | 0..*
Type | ContactPoint
Is Modifier | false
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
24. Subscription.end
Definition | The time for the server to turn the subscription off.
Short | When to automatically delete the subscription
Comments | The server is permitted to deviate from this time but should observe it.
Control | 0..1
Type | instant
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
26. Subscription.reason
Definition | A description of why this subscription is defined.
Short | Description of why this subscription was created
Control | 1..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
28. Subscription.criteria
Definition | When using topic-based subscriptions, the primary criteria is always the topic, indicated by its canonical URL.
Short | Canonical URL for the topic used to generate events
Comments | The rules are search criteria (without the [base] part). Like Bundle.entry.request.url, it has no leading "/".
Control | 1..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
30. Subscription.criteria.id
Definition | unique id for the element within a resource (for internal references)
Short | xml:id (or equivalent in JSON)
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
32. Subscription.criteria.extension
Definition | An Extension
Short | Extension
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `Subscription.criteria.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
34. Subscription.criteria.extension:filterCriteria
Slice Name | filterCriteria
Definition | Search-style filters to be applied to narrow the subscription topic stream. Keys can be either search parameters appropriate to the filtering resource or keys defined within the subscription topic.
Short | Filtering critiera applied to events
Comments | When multiple filters are applied, evaluates to true if all the conditions are met; otherwise it returns false. (i.e., logical AND).
Control | 0..* This element is affected by the following invariants: ele-1
Type | Extension(Backported R5 FilterBy Criteria) (Extension Type: string)
Is Modifier | false
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
36. Subscription.criteria.value
Definition | The actual value
Short | Primitive value for string
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
Max Length: | 1048576
38. Subscription.error
Definition | A record of the last error that occurred when the server processed a notification.
Short | Latest error note
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
40. Subscription.channel
Definition | Details where to send notifications when resources are received that meet the criteria.
Short | The channel on which to report matches to the criteria
Control | 1..1
Type | BackboneElement
Is Modifier | false
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`)
42. Subscription.channel.id
Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.
Short | Unique id for inter-element referencing
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
44. Subscription.channel.extension
Definition | An Extension
Short | Extension
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `Subscription.channel.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
46. Subscription.channel.extension:heartbeatPeriod
Slice Name | heartbeatPeriod
Definition | If present, a 'hearbeat' notification (keepalive) is sent via this channel with an the interval period equal to this elements integer value in seconds. If not present, a heartbeat notification is not sent.
Short | Interval in seconds to send 'heartbeat' notification
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backport R5 Subscription Heartbeat Period) (Extension Type: unsignedInt)
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
48. Subscription.channel.extension:timeout
Slice Name | timeout
Definition | If present, the maximum amount of time a server will allow before failing a notification attempt.
Short | Timeout in seconds to attempt notification delivery
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backport R5 Subscription Timeout) (Extension Type: unsignedInt)
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
50. Subscription.channel.extension:maxCount
Slice Name | maxCount
Definition | If present, the maximum number of triggering resources that will be included in a notification bundle (e.g., a server will not include more than this number of trigger resources in a single notification). Note that this is not a strict limit on the number of entries in a bundle, as dependent resources can be included.
Short | Maximum number of triggering resources included in notification bundles
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backported R5 Subscription MaxCount) (Extension Type: positiveInt)
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
52. Subscription.channel.modifierExtension
Definition | May be used to represent additional information that is not part of the basic definition of the 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).
Short | Extensions that cannot be ignored even if unrecognized
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.
Control | 0..*
Type | Extension
Is Modifier | true because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
Summary | true
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, modifiers
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
54. Subscription.channel.type
Definition | The type of channel to send notifications on.
Short | rest-hook | websocket | email | sms | message
Control | 1..1
Binding | The codes SHALL be taken from SubscriptionChannelType (required to `http://hl7.org/fhir/ValueSet/subscription-channel-type|4.3.0` ) The type of method used to execute a subscription.
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
56. Subscription.channel.type.id
Definition | unique id for the element within a resource (for internal references)
Short | xml:id (or equivalent in JSON)
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
58. Subscription.channel.type.extension
Definition | An Extension
Short | Extension
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `Subscription.channel.type.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
60. Subscription.channel.type.extension:customChannelType
Slice Name | customChannelType
Definition | The type of channel to send notifications on.
Short | Extended channel type for notifications
Comments | This extension allows for the use of additional channel types that were not defined in the FHIR R4 subscription definition.
Control | 0..1 This element is affected by the following invariants: ele-1
Type | Extension(Backported R5 Additional Channel Types) (Extension Type: Coding)
Is Modifier | false
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
62. Subscription.channel.type.value
Definition | Primitive value for code
Short | Primitive value for code
Control | 0..1
Type | code
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
64. Subscription.channel.endpoint
Definition | The url that describes the actual end-point to send messages to.
Short | Where the channel points to
Comments | For rest-hook, and websocket, the end-point must be an http: or https: URL; for email, a mailto: url, for sms, a tel: url, and for message the endpoint can be in any form of url the server understands (usually, http: or mllp:). The URI is allowed to be relative; in which case, it is relative to the server end-point (since there may be more than one, clients should avoid using relative URIs).
Control | 0..1
Type | url
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
66. Subscription.channel.payload
Definition | The mime type to send the payload in - either application/fhir+xml, or application/fhir+json. If the payload is not present, then there is no payload in the notification, just a notification. The mime type "text/plain" may also be used for Email and SMS subscriptions.
Short | MIME type to send, or omit for no payload
Comments | Sending the payload has obvious security implications. The server is responsible for ensuring that the content is appropriately secured.
Control | 1..1
Binding | The codes SHALL be taken from Mime Types (required to `http://hl7.org/fhir/ValueSet/mimetypes|4.3.0` ) BCP 13 (RFCs 2045, 2046, 2047, 4288, 4289 and 2049)
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
68. Subscription.channel.payload.id
Definition | unique id for the element within a resource (for internal references)
Short | xml:id (or equivalent in JSON)
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
70. Subscription.channel.payload.extension
Definition | An Extension
Short | Extension
Control | 1..*
Type | Extension
Is Modifier | false
Summary | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `Subscription.channel.payload.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
72. Subscription.channel.payload.extension:content
Slice Name | content
Definition | How much of the resource content to deliver in the notification payload. The choices are an empty payload, only the resource id, or the full resource content.
Short | Notification content level
Comments | Sending the payload has obvious security implications. The server is responsible for ensuring that the content is appropriately secured.
Control | 1..1 This element is affected by the following invariants: ele-1
Type | Extension(Backport R5 Subscription Payload Content Information) (Extension Type: code)
Is Modifier | false
Must Support | true
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (`hasValue() or (children().count() > id.count()) or $this is Parameters`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
74. Subscription.channel.payload.value
Definition | Primitive value for code
Short | Primitive value for code
Control | 0..1
Type | code
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
76. Subscription.channel.header
Definition | Additional headers / information to send as part of the notification.
Short | Usage depends on the channel type
Comments | Exactly what these mean depend on the channel type. They can convey additional information to the recipient and/or meet security requirements; for example, support of multiple headers in the outgoing notifications for rest-hook type subscriptions.
Control | 0..*
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)