[ERSSUP-81706]-[]-[Swapped Issue code to 'transient']-[JW]

Author: nhsd-jack-wainwright

sandbox/src/mocks/r4/NHSDigital-OperationOutcome-503.json

@@ -6,12 +6,12 @@
     "issue": [
       {
         "severity": "error",
-        "code": "timeout",
+        "code": "transient",
         "details": {
           "coding": [
             {
               "system": "https://fhir.nhs.uk/CodeSystem/http-error-codes",
-              "code": "REC_SERVICE_UNAVAILABLE"
+              "code": "REC_UNAVAILABLE"
             }
           ]
         }

sandbox/src/mocks/stu3/STU3-ServiceUnavailable.json

@@ -8,7 +8,7 @@
     "issue": [
       {
         "severity": "error",
-        "code": "timeout",
+        "code": "transient",
         "details": {
           "coding": [
             {

specification/components/r4/schemas/headers/response/RetryAfter.yaml

@@ -1,6 +1,6 @@
 description: |
   Defines a period (in seconds) after which the client should attempt their request again.
-required: true
+required: false
 schema:
   type: string
   example: '120'

specification/components/r4/schemas/responses/ServiceUnavailable.yaml

@@ -1,10 +1,10 @@
 description: |
   Where status code 503 (Service Unavailable) is returned then an [NHSDigital-OperationOutcome](https://fhir.nhs.uk/StructureDefinition/NHSDigital-OperationOutcome) will be included in the body, as detailed below.
-  In response to receiving this status code, it is recommended that clients retry at a later time based on a returned `Retry-After` header.
+  In response to receiving this status code, it is recommended that clients retry at a later time based on a returned `Retry-After` header when provided.
 
   | issue.details.coding.code | issue.code | Coding System                                                      | Description                                                                                    |
   | ------------------------- | ---------- | ------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------- |
-  | REC_UNAVAILABLE           | timeout    | [BaRS Error Code](https://fhir.nhs.uk/CodeSystem/http-error-codes) | A request to an internal component timed out whilst attempting to serve a response.            |
+  | REC_UNAVAILABLE           | transient  | [BaRS Error Code](https://fhir.nhs.uk/CodeSystem/http-error-codes) | A request to an internal component timed out whilst attempting to serve a response.            |
 
 headers:
   X-Correlation-ID:

specification/components/stu3/schemas/headers/response/RetryAfter.yaml

@@ -1,6 +1,6 @@
 description: |
   Defines a period (in seconds) after which the client should attempt their request again.
-required: true
+required: false
 schema:
   type: string
   example: '120'

specification/components/stu3/schemas/responses/ServiceUnavailable.yaml

@@ -1,6 +1,6 @@
 description: |
   Where status code 503 (Service Unavailable) is returned then an eRS-OperationOutcome-1 will be included in the body, as detailed below.
-  In response to receiving this status code, it is recommended that clients retry at a later time based on a returned `Retry-After` header.
+  In response to receiving this status code, it is recommended that clients retry at a later time based on a returned `Retry-After` header when provided.
   
   | Error code                         | Description                                                                                                                  |
   | ---------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |