diff --git a/internal/events/package.json b/internal/events/package.json
index f21db165..4651a85c 100644
--- a/internal/events/package.json
+++ b/internal/events/package.json
@@ -50,5 +50,5 @@
     "typecheck": "tsc --noEmit"
   },
   "types": "dist/index.d.ts",
-  "version": "1.0.3"
+  "version": "1.1.0"
 }
diff --git a/internal/events/schemas/examples/letter.ACCEPTED.json b/internal/events/schemas/examples/letter.accepted.json
similarity index 80%
rename from internal/events/schemas/examples/letter.ACCEPTED.json
rename to internal/events/schemas/examples/letter.accepted.json
index f9a1177c..2785f8d6 100644
--- a/internal/events/schemas/examples/letter.ACCEPTED.json
+++ b/internal/events/schemas/examples/letter.accepted.json
@@ -5,14 +5,15 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
       "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
     },
     "specificationId": "1y3q9v1zzzz",
-    "status": "ACCEPTED"
+    "status": "ACCEPTED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.ACCEPTED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.accepted.1.0.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -22,5 +23,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.ACCEPTED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.accepted.v1"
 }
diff --git a/internal/events/schemas/examples/letter.cancelled.json b/internal/events/schemas/examples/letter.cancelled.json
new file mode 100644
index 00000000..0cbc4867
--- /dev/null
+++ b/internal/events/schemas/examples/letter.cancelled.json
@@ -0,0 +1,27 @@
+{
+  "data": {
+    "domainId": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+    "groupId": "client_template",
+    "origin": {
+      "domain": "letter-rendering",
+      "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
+      "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
+    },
+    "specificationId": "1y3q9v1zzzz",
+    "status": "CANCELLED",
+    "supplierId": "supplier_12345"
+  },
+  "datacontenttype": "application/json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.cancelled.1.0.0.schema.json",
+  "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
+  "recordedtime": "2025-08-28T08:45:00.000Z",
+  "severitynumber": 2,
+  "severitytext": "INFO",
+  "source": "/data-plane/supplier-api/prod/update-status",
+  "specversion": "1.0",
+  "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
+  "time": "2025-08-28T08:45:00.000Z",
+  "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
+  "type": "uk.nhs.notify.supplier-api.letter.cancelled.v1"
+}
diff --git a/internal/events/schemas/examples/letter.dispatched.json b/internal/events/schemas/examples/letter.dispatched.json
new file mode 100644
index 00000000..e4d8699f
--- /dev/null
+++ b/internal/events/schemas/examples/letter.dispatched.json
@@ -0,0 +1,27 @@
+{
+  "data": {
+    "domainId": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+    "groupId": "client_template",
+    "origin": {
+      "domain": "letter-rendering",
+      "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
+      "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
+    },
+    "specificationId": "1y3q9v1zzzz",
+    "status": "DISPATCHED",
+    "supplierId": "supplier_12345"
+  },
+  "datacontenttype": "application/json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.dispatched.1.0.0.schema.json",
+  "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
+  "recordedtime": "2025-08-28T08:45:00.000Z",
+  "severitynumber": 2,
+  "severitytext": "INFO",
+  "source": "/data-plane/supplier-api/prod/update-status",
+  "specversion": "1.0",
+  "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
+  "time": "2025-08-28T08:45:00.000Z",
+  "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
+  "type": "uk.nhs.notify.supplier-api.letter.dispatched.v1"
+}
diff --git a/internal/events/schemas/examples/letter.failed.json b/internal/events/schemas/examples/letter.failed.json
new file mode 100644
index 00000000..26d12d7c
--- /dev/null
+++ b/internal/events/schemas/examples/letter.failed.json
@@ -0,0 +1,29 @@
+{
+  "data": {
+    "domainId": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+    "groupId": "client_template",
+    "origin": {
+      "domain": "letter-rendering",
+      "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
+      "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
+    },
+    "reasonCode": "X07",
+    "reasonText": "Unprintable",
+    "specificationId": "1y3q9v1zzzz",
+    "status": "FAILED",
+    "supplierId": "supplier_12345"
+  },
+  "datacontenttype": "application/json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.failed.1.0.0.schema.json",
+  "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
+  "recordedtime": "2025-08-28T08:45:00.000Z",
+  "severitynumber": 2,
+  "severitytext": "INFO",
+  "source": "/data-plane/supplier-api/prod/update-status",
+  "specversion": "1.0",
+  "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
+  "time": "2025-08-28T08:45:00.000Z",
+  "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
+  "type": "uk.nhs.notify.supplier-api.letter.failed.v1"
+}
diff --git a/internal/events/src/events/__tests__/testData/letter.FORWARDED.json b/internal/events/schemas/examples/letter.forwarded.json
similarity index 80%
rename from internal/events/src/events/__tests__/testData/letter.FORWARDED.json
rename to internal/events/schemas/examples/letter.forwarded.json
index bf12ed69..144a1585 100644
--- a/internal/events/src/events/__tests__/testData/letter.FORWARDED.json
+++ b/internal/events/schemas/examples/letter.forwarded.json
@@ -5,16 +5,17 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
       "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
     },
     "reasonCode": "RNIB",
     "reasonText": "RNIB",
     "specificationId": "1y3q9v1zzzz",
-    "status": "FORWARDED"
+    "status": "FORWARDED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.FORWARDED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.forwarded.1.0.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -24,5 +25,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.FORWARDED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.forwarded.v1"
 }
diff --git a/internal/events/schemas/examples/letter.rejected.json b/internal/events/schemas/examples/letter.rejected.json
new file mode 100644
index 00000000..1fb881a5
--- /dev/null
+++ b/internal/events/schemas/examples/letter.rejected.json
@@ -0,0 +1,29 @@
+{
+  "data": {
+    "domainId": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+    "groupId": "client_template",
+    "origin": {
+      "domain": "letter-rendering",
+      "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
+      "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
+    },
+    "reasonCode": "Z07",
+    "reasonText": "Invalid",
+    "specificationId": "1y3q9v1zzzz",
+    "status": "REJECTED",
+    "supplierId": "supplier_12345"
+  },
+  "datacontenttype": "application/json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.rejected.1.0.0.schema.json",
+  "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
+  "recordedtime": "2025-08-28T08:45:00.000Z",
+  "severitynumber": 2,
+  "severitytext": "INFO",
+  "source": "/data-plane/supplier-api/prod/update-status",
+  "specversion": "1.0",
+  "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
+  "time": "2025-08-28T08:45:00.000Z",
+  "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
+  "type": "uk.nhs.notify.supplier-api.letter.rejected.v1"
+}
diff --git a/internal/events/src/events/__tests__/testData/letter.RETURNED.json b/internal/events/schemas/examples/letter.returned.json
similarity index 81%
rename from internal/events/src/events/__tests__/testData/letter.RETURNED.json
rename to internal/events/schemas/examples/letter.returned.json
index e273029d..30f77b90 100644
--- a/internal/events/src/events/__tests__/testData/letter.RETURNED.json
+++ b/internal/events/schemas/examples/letter.returned.json
@@ -5,16 +5,17 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
       "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
     },
     "reasonCode": "R07",
     "reasonText": "No such address",
     "specificationId": "1y3q9v1zzzz",
-    "status": "RETURNED"
+    "status": "RETURNED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.RETURNED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.returned.1.0.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -24,5 +25,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.RETURNED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.returned.v1"
 }
diff --git a/internal/events/schemas/supplier-api.yaml b/internal/events/schemas/supplier-api.yaml
index a87277dc..c38c1086 100644
--- a/internal/events/schemas/supplier-api.yaml
+++ b/internal/events/schemas/supplier-api.yaml
@@ -49,10 +49,10 @@ components:
         This indicates that a letter has been accepted for processing by a supplier.
       contentType: application/json
       payload:
-        $ref: './events/letter.ACCEPTED.schema.json'
+        $ref: './events/letter.accepted.schema.json'
       examples:
         - payload:
-            $ref: './examples/letter.ACCEPTED.json'
+            $ref: './examples/letter.accepted.json'
 
     letter-cancelled:
       name: letter-cancelled
@@ -63,7 +63,10 @@ components:
         This indicates that a letter has been cancelled and will not be printed or dispatched.
       contentType: application/json
       payload:
-        $ref: './events/letter.CANCELLED.schema.json'
+        $ref: './events/letter.cancelled.schema.json'
+      examples:
+        - payload:
+            $ref: './examples/letter.cancelled.json'
 
     letter-delivered:
       name: letter-delivered
@@ -74,7 +77,7 @@ components:
         This indicates that a letter has been delivered to the recipient.
       contentType: application/json
       payload:
-        $ref: './events/letter.DELIVERED.schema.json'
+        $ref: './events/letter.delivered.schema.json'
 
     letter-dispatched:
       name: letter-dispatched
@@ -85,7 +88,10 @@ components:
         This indicates that a letter has been dispatched from the supplier to a down-stream access (DSA) provider.
       contentType: application/json
       payload:
-        $ref: './events/letter.DISPATCHED.schema.json'
+        $ref: './events/letter.dispatched.schema.json'
+      examples:
+        - payload:
+            $ref: './examples/letter.dispatched.json'
 
     letter-enclosed:
       name: letter-enclosed
@@ -96,7 +102,7 @@ components:
         This indicates that a letter has been printed and packaged in an envelope.
       contentType: application/json
       payload:
-        $ref: './events/letter.ENCLOSED.schema.json'
+        $ref: './events/letter.enclosed.schema.json'
 
     letter-failed:
       name: letter-failed
@@ -107,7 +113,10 @@ components:
         This indicates that a letter has failed to be processed by a supplier.
       contentType: application/json
       payload:
-        $ref: './events/letter.FAILED.schema.json'
+        $ref: './events/letter.failed.schema.json'
+      examples:
+        - payload:
+            $ref: './examples/letter.failed.json'
 
     letter-forwarded:
       name: letter-forwarded
@@ -118,10 +127,10 @@ components:
         This indicates that a letter has been forwarded to another supplier for processing.
       contentType: application/json
       payload:
-        $ref: './events/letter.FORWARDED.schema.json'
+        $ref: './events/letter.forwarded.schema.json'
       examples:
         - payload:
-            $ref: './examples/letter.FORWARDED.json'
+            $ref: './examples/letter.forwarded.json'
 
     letter-pending:
       name: letter-pending
@@ -132,7 +141,7 @@ components:
         This indicates that a letter has been queued for processing by a supplier.
       contentType: application/json
       payload:
-        $ref: './events/letter.PENDING.schema.json'
+        $ref: './events/letter.pending.schema.json'
 
     letter-printed:
       name: letter-printed
@@ -143,7 +152,7 @@ components:
         This indicates that a letter has been printed by the supplier.
       contentType: application/json
       payload:
-        $ref: './events/letter.PRINTED.schema.json'
+        $ref: './events/letter.printed.schema.json'
 
     letter-rejected:
       name: letter-rejected
@@ -154,7 +163,10 @@ components:
         This indicates that a letter has been rejected by the supplier and will not be processed.
       contentType: application/json
       payload:
-        $ref: './events/letter.REJECTED.schema.json'
+        $ref: './events/letter.rejected.schema.json'
+      examples:
+        - payload:
+            $ref: './examples/letter.rejected.json'
 
     letter-returned:
       name: letter-returned
@@ -165,10 +177,10 @@ components:
         This indicates that a letter has been returned to the supplier.
       contentType: application/json
       payload:
-        $ref: './events/letter.RETURNED.schema.json'
+        $ref: './events/letter.returned.schema.json'
       examples:
         - payload:
-            $ref: './examples/letter.RETURNED.json'
+            $ref: './examples/letter.returned.json'
 
     letter-any:
       name: letter-any
@@ -188,7 +200,7 @@ components:
         This indicates that MI data has been submitted to the NHS Notify Supplier API.
       contentType: application/json
       payload:
-        $ref: './events/mi.SUBMITTED.schema.json'
+        $ref: './events/mi.submitted.schema.json'
 
   schemas:
     letter:
diff --git a/internal/events/src/cli/generate-json.ts b/internal/events/src/cli/generate-json.ts
index a6d35d68..f6ad57ce 100644
--- a/internal/events/src/cli/generate-json.ts
+++ b/internal/events/src/cli/generate-json.ts
@@ -52,6 +52,6 @@ const miJson = z.toJSONSchema($MISubmittedEvent, {
   target: "openapi-3.0",
   reused: "ref",
 });
-const miFile = `schemas/events/mi.SUBMITTED.schema.json`;
+const miFile = `schemas/events/mi.submitted.schema.json`;
 fs.writeFileSync(miFile, JSON.stringify(miJson, null, 2));
-console.info(`Wrote JSON schema for letter.any to ${miFile}`);
+console.info(`Wrote JSON schema for mi.submitted to ${miFile}`);
diff --git a/internal/events/src/domain/letter.ts b/internal/events/src/domain/letter.ts
index 54746591..bce8713b 100644
--- a/internal/events/src/domain/letter.ts
+++ b/internal/events/src/domain/letter.ts
@@ -107,6 +107,12 @@ The identifier will be included as the origin domain in the subject of any corre
           "Optional human-readable reason for the status change, if applicable.",
         examples: ["Undeliverable", "Recipient moved"],
       }),
+
+    supplierId: z.string().meta({
+      title: "Supplier ID",
+      description: "Identifier for the supplier handling this letter.",
+      examples: ["supplier-12345"],
+    }),
   })
   .meta({
     title: "Letter",
diff --git a/internal/events/src/events/__tests__/event-envelope.test.ts b/internal/events/src/events/__tests__/event-envelope.test.ts
index 0ea46e22..c7021476 100644
--- a/internal/events/src/events/__tests__/event-envelope.test.ts
+++ b/internal/events/src/events/__tests__/event-envelope.test.ts
@@ -7,12 +7,12 @@ describe("EventEnvelope schema validation", () => {
 
   const baseValidEnvelope: Envelope = {
     dataschema:
-      "https://notify.nhs.uk/cloudevents/schemas/supplier-api/order.READ.1.0.0.schema.json",
+      "https://notify.nhs.uk/cloudevents/schemas/supplier-api/order.read.1.0.0.schema.json",
     specversion: "1.0",
     id: "6f1c2a53-3d54-4a0a-9a0b-0e9ae2d4c111",
     source: "/data-plane/supplier-api/ordering",
     subject: "order/769acdd4",
-    type: "uk.nhs.notify.supplier-api.order.READ.v1",
+    type: "uk.nhs.notify.supplier-api.order.read.v1",
     time: "2025-10-01T10:15:30.000Z",
     data: {
       "notify-payload": {
@@ -230,7 +230,7 @@ describe("EventEnvelope schema validation", () => {
 
   describe("subject prefix validation", () => {
     const $EnvelopeWithPrefix = EventEnvelope(
-      "letter.CREATED",
+      "letter.created",
       "letter",
       z.any(),
       ["CREATED"],
@@ -240,9 +240,9 @@ describe("EventEnvelope schema validation", () => {
     const baseLetterEnvelope = {
       specversion: "1.0" as const,
       id: "6f1c2a53-3d54-4a0a-9a0b-0e02b2c3d479",
-      type: "uk.nhs.notify.supplier-api.letter.CREATED.v1" as const,
+      type: "uk.nhs.notify.supplier-api.letter.created.v1" as const,
       dataschema:
-        "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.CREATED.1.0.0.schema.json",
+        "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.created.1.0.0.schema.json",
       source: "/data-plane/supplier-api/letters",
       time: "2025-10-01T10:15:30.000Z",
       data: { status: "CREATED" },
@@ -286,16 +286,16 @@ describe("EventEnvelope schema validation", () => {
     });
 
     it("should accept subject without prefix when no prefix is specified", () => {
-      const $EnvelopeNoPrefix = EventEnvelope("order.READ", "order", z.any(), [
+      const $EnvelopeNoPrefix = EventEnvelope("order.read", "order", z.any(), [
         "READ",
       ]);
 
       const envelope = {
         specversion: "1.0" as const,
         id: "6f1c2a53-3d54-4a0a-9a0b-0e9ae2d4c111",
-        type: "uk.nhs.notify.supplier-api.order.READ.v1" as const,
+        type: "uk.nhs.notify.supplier-api.order.read.v1" as const,
         dataschema:
-          "https://notify.nhs.uk/cloudevents/schemas/supplier-api/order.READ.1.0.0.schema.json",
+          "https://notify.nhs.uk/cloudevents/schemas/supplier-api/order.read.1.0.0.schema.json",
         source: "/data-plane/supplier-api/ordering",
         subject: "order/769acdd4",
         time: "2025-10-01T10:15:30.000Z",
@@ -313,7 +313,7 @@ describe("EventEnvelope schema validation", () => {
 
     it("should accept various prefix formats", () => {
       const $EnvelopeMultiSegmentPrefix = EventEnvelope(
-        "letter.CREATED",
+        "letter.created",
         "letter",
         z.any(),
         ["CREATED"],
diff --git a/internal/events/src/events/__tests__/letter-status-change-events.test.ts b/internal/events/src/events/__tests__/letter-status-change-events.test.ts
index 25541fc5..72b9fee9 100644
--- a/internal/events/src/events/__tests__/letter-status-change-events.test.ts
+++ b/internal/events/src/events/__tests__/letter-status-change-events.test.ts
@@ -12,21 +12,24 @@ describe("LetterStatus event validations", () => {
   it.each(["ACCEPTED", "FORWARDED", "RETURNED"])(
     "should parse %s letter statuses successfully",
     (status) => {
-      const json = readJson(`letter.${status}.json`);
+      const statusLower = status.toLowerCase();
+
+      const json = readJson(`letter.${statusLower}.json`);
 
       const { data: event, error } =
-        letterEventMap[`letter.${status}`].safeParse(json);
+        letterEventMap[`letter.${statusLower}`].safeParse(json);
+
       expect(error).toBeUndefined();
       expect(event).toBeDefined();
       expect(event).toEqual(
         expect.objectContaining({
-          type: `uk.nhs.notify.supplier-api.letter.${status}.v1`,
+          type: `uk.nhs.notify.supplier-api.letter.${statusLower}.v1`,
           specversion: "1.0",
           source: "/data-plane/supplier-api/prod/update-status",
           id: "23f1f09c-a555-4d9b-8405-0b33490bc920",
           time: "2025-08-28T08:45:00.000Z",
           datacontenttype: "application/json",
-          dataschema: `https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.${status}.1.0.0.schema.json`,
+          dataschema: `https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.${statusLower}.1.0.0.schema.json`,
           subject:
             "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
           data: expect.objectContaining({
@@ -39,6 +42,7 @@ describe("LetterStatus event validations", () => {
             specificationId: "1y3q9v1zzzz",
             groupId: "client_template",
             status,
+            supplierId: "supplier_12345",
           }),
         }),
       );
@@ -46,9 +50,10 @@ describe("LetterStatus event validations", () => {
   );
 
   it("should parse reason code and text correctly for returned mail", () => {
-    const json = readJson("letter.RETURNED.json");
+    const json = readJson("letter.returned.json");
+
+    const event = letterEventMap["letter.returned"].parse(json);
 
-    const event = letterEventMap["letter.RETURNED"].parse(json);
     expect(event).toBeDefined();
     expect(event.data).toEqual(
       expect.objectContaining({
@@ -59,9 +64,10 @@ describe("LetterStatus event validations", () => {
   });
 
   it("should parse reason code and text correctly for forwarded mail", () => {
-    const json = readJson("letter.FORWARDED.json");
+    const json = readJson("letter.forwarded.json");
+
+    const event = letterEventMap["letter.forwarded"].parse(json);
 
-    const event = letterEventMap["letter.FORWARDED"].parse(json);
     expect(event).toBeDefined();
     expect(event.data).toEqual(
       expect.objectContaining({
@@ -71,18 +77,18 @@ describe("LetterStatus event validations", () => {
     );
   });
 
-  it("should throw error for letter.ACCEPTED event with missing sourceSubject", () => {
-    const json = readJson("letter.ACCEPTED-with-missing-fields.json");
+  it("should throw error for letter.accepted event with missing sourceSubject", () => {
+    const json = readJson("letter.accepted-with-missing-fields.json");
 
-    expect(() => letterEventMap["letter.ACCEPTED"].parse(json)).toThrow(
+    expect(() => letterEventMap["letter.accepted"].parse(json)).toThrow(
       "subject",
     );
   });
 
-  it("should throw error for letter.ACCEPTED event with invalid major schema version", () => {
-    const json = readJson("letter.ACCEPTED-with-invalid-major-version.json");
+  it("should throw error for letter.accepted event with invalid major schema version", () => {
+    const json = readJson("letter.accepted-with-invalid-major-version.json");
 
-    expect(() => letterEventMap["letter.ACCEPTED"].parse(json)).toThrow(
+    expect(() => letterEventMap["letter.accepted"].parse(json)).toThrow(
       "dataschema",
     );
   });
diff --git a/internal/events/src/events/__tests__/mi-events.test.ts b/internal/events/src/events/__tests__/mi-events.test.ts
index 565ab7dc..be00ba18 100644
--- a/internal/events/src/events/__tests__/mi-events.test.ts
+++ b/internal/events/src/events/__tests__/mi-events.test.ts
@@ -9,22 +9,22 @@ function readJson(filename: string): unknown {
 }
 
 describe("MI event validations", () => {
-  it("should parse mi.SUBMITTED event successfully", () => {
-    const json = readJson("mi.SUBMITTED.json");
+  it("should parse mi.submitted event successfully", () => {
+    const json = readJson("mi.submitted.json");
 
     const { data: event, error } = $MISubmittedEvent.safeParse(json);
     expect(error).toBeUndefined();
     expect(event).toBeDefined();
     expect(event).toEqual(
       expect.objectContaining({
-        type: "uk.nhs.notify.supplier-api.mi.SUBMITTED.v1",
+        type: "uk.nhs.notify.supplier-api.mi.submitted.v1",
         specversion: "1.0",
         source: "/data-plane/supplier-api/prod/submit-mi",
         id: "8f2c3b44-4e65-5b1b-a678-1f0bf3d4d222",
         time: "2025-11-16T10:30:00.000Z",
         datacontenttype: "application/json",
         dataschema:
-          "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.SUBMITTED.1.0.0.schema.json",
+          "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.submitted.1.0.0.schema.json",
         subject: "mi/mi-test-001",
         data: expect.objectContaining({
           id: "mi-test-001",
@@ -40,8 +40,8 @@ describe("MI event validations", () => {
     );
   });
 
-  it("should parse minimal mi.SUBMITTED event successfully", () => {
-    const json = readJson("mi.SUBMITTED-minimal.json");
+  it("should parse minimal mi.submitted event successfully", () => {
+    const json = readJson("mi.submitted-minimal.json");
 
     const event = $MISubmittedEvent.parse(json);
     expect(event).toBeDefined();
@@ -59,7 +59,7 @@ describe("MI event validations", () => {
   });
 
   it("should parse MI data fields correctly", () => {
-    const json = readJson("mi.SUBMITTED.json");
+    const json = readJson("mi.submitted.json");
 
     const event = $MISubmittedEvent.parse(json);
     expect(event).toBeDefined();
@@ -72,14 +72,14 @@ describe("MI event validations", () => {
     expect(event.data.groupId).toBe("group-456");
   });
 
-  it("should throw error for mi.SUBMITTED event with missing subject", () => {
-    const json = readJson("mi.SUBMITTED-with-missing-subject.json");
+  it("should throw error for mi.submitted event with missing subject", () => {
+    const json = readJson("mi.submitted-with-missing-subject.json");
 
     expect(() => $MISubmittedEvent.parse(json)).toThrow("subject");
   });
 
-  it("should throw error for mi.SUBMITTED event with invalid major schema version", () => {
-    const json = readJson("mi.SUBMITTED-with-invalid-major-version.json");
+  it("should throw error for mi.submitted event with invalid major schema version", () => {
+    const json = readJson("mi.submitted-with-invalid-major-version.json");
 
     expect(() => $MISubmittedEvent.parse(json)).toThrow("dataschema");
   });
diff --git a/internal/events/src/events/__tests__/testData/letter.ACCEPTED.json b/internal/events/src/events/__tests__/testData/letter.accepted-with-invalid-major-version.json
similarity index 80%
rename from internal/events/src/events/__tests__/testData/letter.ACCEPTED.json
rename to internal/events/src/events/__tests__/testData/letter.accepted-with-invalid-major-version.json
index f9a1177c..0d9f0898 100644
--- a/internal/events/src/events/__tests__/testData/letter.ACCEPTED.json
+++ b/internal/events/src/events/__tests__/testData/letter.accepted-with-invalid-major-version.json
@@ -5,14 +5,15 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
       "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
     },
     "specificationId": "1y3q9v1zzzz",
-    "status": "ACCEPTED"
+    "status": "ACCEPTED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.ACCEPTED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.accepted.0.1.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -22,5 +23,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.ACCEPTED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.accepted.v1"
 }
diff --git a/internal/events/src/events/__tests__/testData/letter.ACCEPTED-with-missing-fields.json b/internal/events/src/events/__tests__/testData/letter.accepted-with-missing-fields.json
similarity index 77%
rename from internal/events/src/events/__tests__/testData/letter.ACCEPTED-with-missing-fields.json
rename to internal/events/src/events/__tests__/testData/letter.accepted-with-missing-fields.json
index bb5d8021..97647559 100644
--- a/internal/events/src/events/__tests__/testData/letter.ACCEPTED-with-missing-fields.json
+++ b/internal/events/src/events/__tests__/testData/letter.accepted-with-missing-fields.json
@@ -5,13 +5,14 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf"
+      "source": "/data-plane/letter-rendering/prod/letter-renderer"
     },
     "specificationId": "1y3q9v1zzzz",
-    "status": "ACCEPTED"
+    "status": "ACCEPTED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.ACCEPTED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.accepted.1.0.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -21,5 +22,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.ACCEPTED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.accepted.v1"
 }
diff --git a/internal/events/src/events/__tests__/testData/letter.ACCEPTED-with-invalid-major-version.json b/internal/events/src/events/__tests__/testData/letter.accepted.json
similarity index 80%
rename from internal/events/src/events/__tests__/testData/letter.ACCEPTED-with-invalid-major-version.json
rename to internal/events/src/events/__tests__/testData/letter.accepted.json
index 95e95651..2785f8d6 100644
--- a/internal/events/src/events/__tests__/testData/letter.ACCEPTED-with-invalid-major-version.json
+++ b/internal/events/src/events/__tests__/testData/letter.accepted.json
@@ -5,14 +5,15 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
       "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
     },
     "specificationId": "1y3q9v1zzzz",
-    "status": "ACCEPTED"
+    "status": "ACCEPTED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.ACCEPTED.0.1.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.accepted.1.0.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -22,5 +23,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.ACCEPTED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.accepted.v1"
 }
diff --git a/internal/events/schemas/examples/letter.FORWARDED.json b/internal/events/src/events/__tests__/testData/letter.forwarded.json
similarity index 80%
rename from internal/events/schemas/examples/letter.FORWARDED.json
rename to internal/events/src/events/__tests__/testData/letter.forwarded.json
index bf12ed69..144a1585 100644
--- a/internal/events/schemas/examples/letter.FORWARDED.json
+++ b/internal/events/src/events/__tests__/testData/letter.forwarded.json
@@ -5,16 +5,17 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
       "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
     },
     "reasonCode": "RNIB",
     "reasonText": "RNIB",
     "specificationId": "1y3q9v1zzzz",
-    "status": "FORWARDED"
+    "status": "FORWARDED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.FORWARDED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.forwarded.1.0.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -24,5 +25,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.FORWARDED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.forwarded.v1"
 }
diff --git a/internal/events/schemas/examples/letter.RETURNED.json b/internal/events/src/events/__tests__/testData/letter.returned.json
similarity index 81%
rename from internal/events/schemas/examples/letter.RETURNED.json
rename to internal/events/src/events/__tests__/testData/letter.returned.json
index e273029d..30f77b90 100644
--- a/internal/events/schemas/examples/letter.RETURNED.json
+++ b/internal/events/src/events/__tests__/testData/letter.returned.json
@@ -5,16 +5,17 @@
     "origin": {
       "domain": "letter-rendering",
       "event": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
-      "source": "/data-plane/letter-rendering/prod/render-pdf",
+      "source": "/data-plane/letter-rendering/prod/letter-renderer",
       "subject": "client/00f3b388-bbe9-41c9-9e76-052d37ee8988/letter-request/0o5Fs0EELR0fUjHjbCnEtdUwQe4_0o5Fs0EELR0fUjHjbCnEtdUwQe5"
     },
     "reasonCode": "R07",
     "reasonText": "No such address",
     "specificationId": "1y3q9v1zzzz",
-    "status": "RETURNED"
+    "status": "RETURNED",
+    "supplierId": "supplier_12345"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.RETURNED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.returned.1.0.0.schema.json",
   "id": "23f1f09c-a555-4d9b-8405-0b33490bc920",
   "recordedtime": "2025-08-28T08:45:00.000Z",
   "severitynumber": 2,
@@ -24,5 +25,5 @@
   "subject": "letter-origin/letter-rendering/letter/f47ac10b-58cc-4372-a567-0e02b2c3d479",
   "time": "2025-08-28T08:45:00.000Z",
   "traceparent": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01",
-  "type": "uk.nhs.notify.supplier-api.letter.RETURNED.v1"
+  "type": "uk.nhs.notify.supplier-api.letter.returned.v1"
 }
diff --git a/internal/events/src/events/__tests__/testData/mi.SUBMITTED-minimal.json b/internal/events/src/events/__tests__/testData/mi.submitted-minimal.json
similarity index 88%
rename from internal/events/src/events/__tests__/testData/mi.SUBMITTED-minimal.json
rename to internal/events/src/events/__tests__/testData/mi.submitted-minimal.json
index fd1cd1be..ba19f560 100644
--- a/internal/events/src/events/__tests__/testData/mi.SUBMITTED-minimal.json
+++ b/internal/events/src/events/__tests__/testData/mi.submitted-minimal.json
@@ -10,7 +10,7 @@
     "updatedAt": "2025-11-16T15:00:00.000Z"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.SUBMITTED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.submitted.1.0.0.schema.json",
   "id": "9a3d4c55-5f76-6c2c-b789-2f1cf4e5e333",
   "recordedtime": "2025-11-16T15:00:00.250Z",
   "severitynumber": 2,
@@ -20,5 +20,5 @@
   "subject": "mi/mi-envelope-001",
   "time": "2025-11-16T15:00:00.000Z",
   "traceparent": "00-2cf9873938ef65ff0660fd433e02541e-d9cf8d9380415553-01",
-  "type": "uk.nhs.notify.supplier-api.mi.SUBMITTED.v1"
+  "type": "uk.nhs.notify.supplier-api.mi.submitted.v1"
 }
diff --git a/internal/events/src/events/__tests__/testData/mi.SUBMITTED-with-invalid-major-version.json b/internal/events/src/events/__tests__/testData/mi.submitted-with-invalid-major-version.json
similarity index 89%
rename from internal/events/src/events/__tests__/testData/mi.SUBMITTED-with-invalid-major-version.json
rename to internal/events/src/events/__tests__/testData/mi.submitted-with-invalid-major-version.json
index 5c51190a..1b319346 100644
--- a/internal/events/src/events/__tests__/testData/mi.SUBMITTED-with-invalid-major-version.json
+++ b/internal/events/src/events/__tests__/testData/mi.submitted-with-invalid-major-version.json
@@ -12,7 +12,7 @@
     "updatedAt": "2025-11-16T10:30:00.000Z"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.SUBMITTED.2.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.submitted.2.0.0.schema.json",
   "id": "8f2c3b44-4e65-5b1b-a678-1f0bf3d4d222",
   "recordedtime": "2025-11-16T10:30:00.250Z",
   "severitynumber": 2,
@@ -22,5 +22,5 @@
   "subject": "mi/mi-test-001",
   "time": "2025-11-16T10:30:00.000Z",
   "traceparent": "00-1bf8762827de54ee9559fc322d91430d-c8be7c8279304442-01",
-  "type": "uk.nhs.notify.supplier-api.mi.SUBMITTED.v1"
+  "type": "uk.nhs.notify.supplier-api.mi.submitted.v1"
 }
diff --git a/internal/events/src/events/__tests__/testData/mi.SUBMITTED-with-missing-subject.json b/internal/events/src/events/__tests__/testData/mi.submitted-with-missing-subject.json
similarity index 88%
rename from internal/events/src/events/__tests__/testData/mi.SUBMITTED-with-missing-subject.json
rename to internal/events/src/events/__tests__/testData/mi.submitted-with-missing-subject.json
index e0be7a8e..9fb85d0a 100644
--- a/internal/events/src/events/__tests__/testData/mi.SUBMITTED-with-missing-subject.json
+++ b/internal/events/src/events/__tests__/testData/mi.submitted-with-missing-subject.json
@@ -9,7 +9,7 @@
     "updatedAt": "2025-11-16T10:30:00.000Z"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.SUBMITTED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.submitted.1.0.0.schema.json",
   "id": "8f2c3b44-4e65-5b1b-a678-1f0bf3d4d222",
   "recordedtime": "2025-11-16T10:30:00.250Z",
   "severitynumber": 2,
@@ -18,5 +18,5 @@
   "specversion": "1.0",
   "time": "2025-11-16T10:30:00.000Z",
   "traceparent": "00-1bf8762827de54ee9559fc322d91430d-c8be7c8279304442-01",
-  "type": "uk.nhs.notify.supplier-api.mi.SUBMITTED.v1"
+  "type": "uk.nhs.notify.supplier-api.mi.submitted.v1"
 }
diff --git a/internal/events/src/events/__tests__/testData/mi.SUBMITTED.json b/internal/events/src/events/__tests__/testData/mi.submitted.json
similarity index 89%
rename from internal/events/src/events/__tests__/testData/mi.SUBMITTED.json
rename to internal/events/src/events/__tests__/testData/mi.submitted.json
index 6e2c031d..9bbc27de 100644
--- a/internal/events/src/events/__tests__/testData/mi.SUBMITTED.json
+++ b/internal/events/src/events/__tests__/testData/mi.submitted.json
@@ -12,7 +12,7 @@
     "updatedAt": "2025-11-16T10:30:00.000Z"
   },
   "datacontenttype": "application/json",
-  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.SUBMITTED.1.0.0.schema.json",
+  "dataschema": "https://notify.nhs.uk/cloudevents/schemas/supplier-api/mi.submitted.1.0.0.schema.json",
   "id": "8f2c3b44-4e65-5b1b-a678-1f0bf3d4d222",
   "recordedtime": "2025-11-16T10:30:00.250Z",
   "severitynumber": 2,
@@ -22,5 +22,5 @@
   "subject": "mi/mi-test-001",
   "time": "2025-11-16T10:30:00.000Z",
   "traceparent": "00-1bf8762827de54ee9559fc322d91430d-c8be7c8279304442-01",
-  "type": "uk.nhs.notify.supplier-api.mi.SUBMITTED.v1"
+  "type": "uk.nhs.notify.supplier-api.mi.submitted.v1"
 }
diff --git a/internal/events/src/events/event-envelope.ts b/internal/events/src/events/event-envelope.ts
index a040fe9d..23fe0851 100644
--- a/internal/events/src/events/event-envelope.ts
+++ b/internal/events/src/events/event-envelope.ts
@@ -8,7 +8,7 @@ export function EventEnvelope<TData extends z.ZodTypeAny>(
   statuses: readonly string[],
   subjectPrefix?: string,
 ) {
-  const statusRegex = statuses.join("|");
+  const statusRegex = statuses.map((status) => status.toLowerCase()).join("|");
   const subjectPrefixRegex = subjectPrefix
     ? `${subjectPrefix}/[a-z0-9-]+/`
     : "";
@@ -19,12 +19,12 @@ export function EventEnvelope<TData extends z.ZodTypeAny>(
   // Pre-compute type strings to avoid repeated inference
   const typeStrings = statuses.map(
     (status) =>
-      `uk.nhs.notify.supplier-api.${resourceName}.${status}.v1` as const,
+      `uk.nhs.notify.supplier-api.${resourceName}.${status.toLowerCase()}.v1` as const,
   );
 
   const schemaExamples = statuses.map(
     (status) =>
-      `https://notify.nhs.uk/cloudevents/schemas/supplier-api/${resourceName}.${status}.1.0.0.schema.json`,
+      `https://notify.nhs.uk/cloudevents/schemas/supplier-api/${resourceName}.${status.toLowerCase()}.1.0.0.schema.json`,
   );
 
   return z
diff --git a/internal/events/src/events/letter-events.ts b/internal/events/src/events/letter-events.ts
index 49795068..5dcc0db2 100644
--- a/internal/events/src/events/letter-events.ts
+++ b/internal/events/src/events/letter-events.ts
@@ -25,21 +25,24 @@ export type LetterEvent = z.infer<typeof $LetterEvent>;
  * Specialise the generic event schema for a single status
  * @param status
  */
-const eventSchema = (status: LetterStatus) =>
-  EventEnvelope(
-    `letter.${status}`,
+const eventSchema = (status: LetterStatus) => {
+  const statusLower = status.toLowerCase();
+
+  return EventEnvelope(
+    `letter.${statusLower}`,
     "letter",
     $Letter,
     [status],
     "letter-origin",
   ).meta({
-    title: `letter.${status} Event`,
+    title: `letter.${statusLower} Event`,
     description: `Event schema for letter status change to ${status}`,
   });
+};
 
 export const letterEventMap = Object.fromEntries(
   $LetterStatus.options.map((status) => [
-    `letter.${status}`,
+    `letter.${status.toLowerCase()}`,
     eventSchema(status),
   ]),
 );
diff --git a/internal/events/src/events/mi-events.ts b/internal/events/src/events/mi-events.ts
index b6d4e44d..f1456a9d 100644
--- a/internal/events/src/events/mi-events.ts
+++ b/internal/events/src/events/mi-events.ts
@@ -2,10 +2,10 @@ import { z } from "zod";
 import { EventEnvelope } from "@nhsdigital/nhs-notify-event-schemas-supplier-api/src/events/event-envelope";
 import { $MI } from "@nhsdigital/nhs-notify-event-schemas-supplier-api/src/domain/mi";
 
-export const $MISubmittedEvent = EventEnvelope("mi.SUBMITTED", "mi", $MI, [
+export const $MISubmittedEvent = EventEnvelope("mi.submitted", "mi", $MI, [
   "SUBMITTED",
 ]).meta({
-  title: `mi.SUBMITTED Event`,
+  title: `mi.submitted Event`,
   description: `Event schema for reporting that MI data has been submitted`,
 });
 export type MISubmittedEvent = z.infer<typeof $MISubmittedEvent>;
diff --git a/internal/events/src/index.ts b/internal/events/src/index.ts
index c4255d26..339ddcd6 100644
--- a/internal/events/src/index.ts
+++ b/internal/events/src/index.ts
@@ -4,3 +4,4 @@ export { default as DomainBase } from "./domain/domain-base";
 export * from "./events/event-envelope";
 export * from "./events/letter-events";
 export * from "./events/mi-events";
+export * from "./version";
diff --git a/internal/events/src/version.ts b/internal/events/src/version.ts
new file mode 100644
index 00000000..94e4e78d
--- /dev/null
+++ b/internal/events/src/version.ts
@@ -0,0 +1,5 @@
+import { version } from "../package.json";
+
+export { version as VERSION } from "../package.json";
+
+export const [MAJOR_VERSION] = version.split(".");
diff --git a/package-lock.json b/package-lock.json
index 84d490ac..ad43ac53 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -99,7 +99,7 @@
     },
     "internal/events": {
       "name": "@nhsdigital/nhs-notify-event-schemas-supplier-api",
-      "version": "1.0.3",
+      "version": "1.1.0",
       "license": "MIT",
       "dependencies": {
         "@asyncapi/bundler": "^0.6.4",