diff --git a/Makefile b/Makefile
index ff6edecb3c..729bcfa838 100644
--- a/Makefile
+++ b/Makefile
@@ -210,6 +210,23 @@ emit-object-tags-added-without-virus: ##@events emits a ObjectTagging:Put event
 		--function-name event-received text \
 		--payload '{"Records":[{"eventSource":"aws:s3","eventTime":"2023-10-23T15:58:33.081Z","eventName":"ObjectTagging:Put","s3":{"bucket":{"name":"uploads-opg-modernising-lpa-eu-west-1"},"object":{"key":"$(key)"}}}]}'
 
+emit-immaterial-change-confirmed: ##@events emits a immaterial-change-confirmed event with the given LpaUID, actor type an actor UID e.g. emit-immaterial-change-confirmed uid=abc-123 actorType=donor actorUid=def-456
+	$(eval BODY := $(shell echo '{"version":"0","id":"63eb7e5f-1f10-4744-bba9-e16d327c3b98","detail-type":"immaterial-change-confirmed","source":"opg.poas.sirius","account":"653761790766","time":"2023-08-30T13:40:30Z","region":"eu-west-1","resources":[],"detail":{"uid":"$(uid)","actorType":"$(actorType)","actorUid":"$(actorUid)","sentDate":"2024-01-02T12:13:14.000006Z"}}' | sed 's/"/\\"/g'))
+
+	docker compose -f docker/docker-compose.yml exec localstack awslocal lambda invoke \
+		--endpoint-url=http://localhost:4566 \
+		--region eu-west-1 \
+		--function-name event-received text \
+		--payload '{"Records": [{"messageId": "19dd0b57-b21e-4ac1-bd88-01bbb068cb78", "body": "$(BODY)"}]}'
+
+emit-material-change-confirmed: ##@events emits a material-change-confirmed event with the given LpaUID, actor type an actor UID e.g. emit-material-change-confirmed uid=abc-123 actorType=donor actorUid=def-456
+	$(eval BODY := $(shell echo '{"version":"0","id":"63eb7e5f-1f10-4744-bba9-e16d327c3b98","detail-type":"material-change-confirmed","source":"opg.poas.sirius","account":"653761790766","time":"2023-08-30T13:40:30Z","region":"eu-west-1","resources":[],"detail":{"uid":"$(uid)","actorType":"$(actorType)","actorUid":"$(actorUid)","sentDate":"2024-01-02T12:13:14.000006Z"}}' | sed 's/"/\\"/g'))
+
+	docker compose -f docker/docker-compose.yml exec localstack awslocal lambda invoke \
+		--endpoint-url=http://localhost:4566 \
+		--region eu-west-1 \
+		--function-name event-received text \
+		--payload '{"Records": [{"messageId": "19dd0b57-b21e-4ac1-bd88-01bbb068cb78", "body": "$(BODY)"}]}'
 
 set-uploads-clean: ##@events calls emit-object-tags-added-without-virus for all documents on a given lpa e.g. set-uploads-clean lpaId=abc
 	for k in $$(docker compose -f docker/docker-compose.yml exec localstack awslocal dynamodb --region eu-west-1 query --table-name lpas --key-condition-expression 'PK = :pk and begins_with(SK, :sk)' --expression-attribute-values '{":pk": {"S": "LPA#$(lpaId)"}, ":sk": {"S": "DOCUMENT#"}}' | jq -c -r '.Items[] | .Key[]'); do \
diff --git a/cmd/event-received/handlers.go b/cmd/event-received/handlers.go
index 87e67876f8..2faa92ba0a 100644
--- a/cmd/event-received/handlers.go
+++ b/cmd/event-received/handlers.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/aws/aws-lambda-go/events"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/certificateprovider/certificateproviderdata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/donor/donordata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/dynamo"
 )
@@ -78,3 +79,27 @@ func getDonorByLpaUID(ctx context.Context, client dynamodbClient, uid string) (*
 
 	return &donor, nil
 }
+
+func putCertificateProvider(ctx context.Context, certificateProvider *certificateproviderdata.Provided, now func() time.Time, client dynamodbClient) error {
+	certificateProvider.UpdatedAt = now()
+
+	return client.Put(ctx, certificateProvider)
+}
+
+func getCertificateProviderByLpaUID(ctx context.Context, client dynamodbClient, uid string) (*certificateproviderdata.Provided, error) {
+	var key dynamo.Keys
+	if err := client.OneByUID(ctx, uid, &key); err != nil {
+		return nil, fmt.Errorf("failed to resolve uid: %w", err)
+	}
+
+	if key.PK == nil {
+		return nil, fmt.Errorf("PK missing from LPA in response")
+	}
+
+	var certificateProvider certificateproviderdata.Provided
+	if err := client.OneByPartialSK(ctx, key.PK, dynamo.CertificateProviderKey(""), &certificateProvider); err != nil {
+		return nil, fmt.Errorf("failed to get certificate provider: %w", err)
+	}
+
+	return &certificateProvider, nil
+}
diff --git a/cmd/event-received/mock_test.go b/cmd/event-received/mock_test.go
index 449965bfd8..ca07fecdeb 100644
--- a/cmd/event-received/mock_test.go
+++ b/cmd/event-received/mock_test.go
@@ -15,14 +15,21 @@ func (c *mockDynamodbClient_OneByUID_Call) SetData(data any) {
 }
 
 func (c *mockDynamodbClient_One_Call) SetData(data any) {
-	c.Run(func(_ context.Context, _ dynamo.PK, _ dynamo.SK, v interface{}) {
+	c.Run(func(_ context.Context, _ dynamo.PK, _ dynamo.SK, v any) {
 		b, _ := attributevalue.Marshal(data)
 		attributevalue.Unmarshal(b, v)
 	})
 }
 
 func (c *mockDynamodbClient_AllByLpaUIDAndPartialSK_Call) SetData(data any) {
-	c.Run(func(_ context.Context, _ string, _ dynamo.SK, v interface{}) {
+	c.Run(func(_ context.Context, _ string, _ dynamo.SK, v any) {
+		b, _ := attributevalue.Marshal(data)
+		attributevalue.Unmarshal(b, v)
+	})
+}
+
+func (c *mockDynamodbClient_OneByPartialSK_Call) SetData(data any) {
+	c.Run(func(_ context.Context, _ dynamo.PK, _ dynamo.SK, v any) {
 		b, _ := attributevalue.Marshal(data)
 		attributevalue.Unmarshal(b, v)
 	})
diff --git a/cmd/event-received/sirius_event_handler.go b/cmd/event-received/sirius_event_handler.go
index 2c44fb9288..8afab2b60d 100644
--- a/cmd/event-received/sirius_event_handler.go
+++ b/cmd/event-received/sirius_event_handler.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/aws/aws-lambda-go/events"
+	"github.com/ministryofjustice/opg-modernising-lpa/internal/actor"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/appcontext"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/certificateprovider/certificateproviderdata"
 	"github.com/ministryofjustice/opg-modernising-lpa/internal/donor/donordata"
@@ -76,6 +77,12 @@ func (h *siriusEventHandler) Handle(ctx context.Context, factory factory, cloudW
 	case "priority-correspondence-sent":
 		return handlePriorityCorrespondenceSent(ctx, factory.DynamoClient(), cloudWatchEvent, factory.Now())
 
+	case "immaterial-change-confirmed":
+		return handleChangeConfirmed(ctx, factory.DynamoClient(), cloudWatchEvent, factory.Now(), false)
+
+	case "material-change-confirmed":
+		return handleChangeConfirmed(ctx, factory.DynamoClient(), cloudWatchEvent, factory.Now(), true)
+
 	default:
 		return fmt.Errorf("unknown sirius event")
 	}
@@ -120,7 +127,7 @@ func handleFeeApproved(
 
 	donor, err := getDonorByLpaUID(ctx, client, v.UID)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to get donor: %w", err)
 	}
 
 	if donor.Tasks.PayForLpa.IsCompleted() || donor.Tasks.PayForLpa.IsApproved() {
@@ -168,7 +175,7 @@ func handleFurtherInfoRequested(ctx context.Context, client dynamodbClient, even
 
 	donor, err := getDonorByLpaUID(ctx, client, v.UID)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to get donor: %w", err)
 	}
 
 	if donor.Tasks.PayForLpa.IsMoreEvidenceRequired() {
@@ -193,7 +200,7 @@ func handleFeeDenied(ctx context.Context, client dynamodbClient, event *events.C
 
 	donor, err := getDonorByLpaUID(ctx, client, v.UID)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to get donor: %w", err)
 	}
 
 	if donor.Tasks.PayForLpa.IsDenied() {
@@ -333,13 +340,67 @@ func handlePriorityCorrespondenceSent(ctx context.Context, client dynamodbClient
 
 	donor, err := getDonorByLpaUID(ctx, client, v.UID)
 	if err != nil {
-		return fmt.Errorf("failed to get lpa: %w", err)
+		return fmt.Errorf("failed to get donor: %w", err)
 	}
 
 	donor.PriorityCorrespondenceSentAt = v.SentDate
 
 	if err := putDonor(ctx, donor, now, client); err != nil {
-		return fmt.Errorf("failed to update lpa: %w", err)
+		return fmt.Errorf("failed to update donor: %w", err)
+	}
+
+	return nil
+}
+
+type changeConfirmedEvent struct {
+	UID       string     `json:"uid"`
+	ActorType actor.Type `json:"actorType"`
+	ActorUID  string     `json:"actorUID"`
+}
+
+func handleChangeConfirmed(ctx context.Context, client dynamodbClient, event *events.CloudWatchEvent, now func() time.Time, materialChange bool) error {
+	var v changeConfirmedEvent
+	if err := json.Unmarshal(event.Detail, &v); err != nil {
+		return fmt.Errorf("failed to unmarshal detail: %w", err)
+	}
+
+	switch v.ActorType {
+	case actor.TypeDonor:
+		donor, err := getDonorByLpaUID(ctx, client, v.UID)
+		if err != nil {
+			return fmt.Errorf("failed to get donor: %w", err)
+		}
+
+		if donor.Tasks.ConfirmYourIdentity.IsProblem() {
+			if materialChange {
+				donor.MaterialChangeConfirmedAt = now()
+			} else {
+				donor.Tasks.ConfirmYourIdentity = task.IdentityStateCompleted
+			}
+
+			if err := putDonor(ctx, donor, now, client); err != nil {
+				return fmt.Errorf("failed to update donor: %w", err)
+			}
+		}
+	case actor.TypeCertificateProvider:
+		certificateProvider, err := getCertificateProviderByLpaUID(ctx, client, v.UID)
+		if err != nil {
+			return fmt.Errorf("failed to get certificate provider: %w", err)
+		}
+
+		if certificateProvider.Tasks.ConfirmYourIdentity.IsProblem() {
+			if materialChange {
+				certificateProvider.MaterialChangeConfirmedAt = now()
+			} else {
+				certificateProvider.Tasks.ConfirmYourIdentity = task.IdentityStateCompleted
+			}
+
+			if err := putCertificateProvider(ctx, certificateProvider, now, client); err != nil {
+				return fmt.Errorf("failed to update certificate provider: %w", err)
+			}
+		}
+	default:
+		return fmt.Errorf("invalid actorType, got %s, want donor or certificateProvider", v.ActorType.String())
 	}
 
 	return nil
diff --git a/cmd/event-received/sirius_event_handler_test.go b/cmd/event-received/sirius_event_handler_test.go
index bd3076f44f..202595549f 100644
--- a/cmd/event-received/sirius_event_handler_test.go
+++ b/cmd/event-received/sirius_event_handler_test.go
@@ -1406,3 +1406,310 @@ func TestHandlePriorityCorrespondenceSentWhenPutError(t *testing.T) {
 	err := handlePriorityCorrespondenceSent(ctx, client, event, testNowFn)
 	assert.ErrorIs(t, err, expectedError)
 }
+
+func TestHandleImmaterialChangeConfirmed(t *testing.T) {
+	testcases := map[string]struct {
+		setupDynamoClient func() *mockDynamodbClient
+	}{
+		"donor": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				updated := &donordata.Provided{
+					PK:        dynamo.LpaKey("123"),
+					SK:        dynamo.LpaOwnerKey(dynamo.DonorKey("456")),
+					Tasks:     donordata.Tasks{ConfirmYourIdentity: task.IdentityStateCompleted},
+					UpdatedAt: testNow,
+				}
+				updated.UpdateHash()
+
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(ctx, "M-1111-2222-3333", mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					One(ctx, dynamo.LpaKey("123"), dynamo.DonorKey("456"), mock.Anything).
+					Return(nil).
+					SetData(donordata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.LpaOwnerKey(dynamo.DonorKey("456")),
+						Tasks: donordata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+					})
+				c.EXPECT().
+					Put(ctx, updated).
+					Return(nil)
+
+				return c
+			},
+		},
+		"certificateProvider": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(ctx, "M-1111-2222-3333", mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					OneByPartialSK(ctx, dynamo.LpaKey("123"), dynamo.CertificateProviderKey(""), mock.Anything).
+					Return(nil).
+					SetData(&certificateproviderdata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.CertificateProviderKey("789"),
+						Tasks: certificateproviderdata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+					})
+				c.EXPECT().
+					Put(ctx, &certificateproviderdata.Provided{
+						PK:        dynamo.LpaKey("123"),
+						SK:        dynamo.CertificateProviderKey("789"),
+						Tasks:     certificateproviderdata.Tasks{ConfirmYourIdentity: task.IdentityStateCompleted},
+						UpdatedAt: testNow,
+					}).
+					Return(nil)
+
+				return c
+			},
+		},
+	}
+
+	for actorType, tc := range testcases {
+		t.Run(actorType, func(t *testing.T) {
+			event := &events.CloudWatchEvent{
+				DetailType: "immaterial-change-confirmed",
+				Detail:     json.RawMessage(fmt.Sprintf(`{"uid":"M-1111-2222-3333","actorUID":"740e5834-3a29-46b4-9a6f-16142fde533a","actorType":"%s"}`, actorType)),
+			}
+
+			factory := newMockFactory(t)
+			factory.EXPECT().
+				DynamoClient().
+				Return(tc.setupDynamoClient())
+			factory.EXPECT().
+				Now().
+				Return(testNowFn)
+
+			handler := &siriusEventHandler{}
+			err := handler.Handle(ctx, factory, event)
+
+			assert.Nil(t, err)
+		})
+	}
+}
+
+func TestHandleChangeConfirmedWhenIdentityTaskNotProblem(t *testing.T) {
+	testcases := map[string]struct {
+		setupDynamoClient func() *mockDynamodbClient
+	}{
+		"donor": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(ctx, "M-1111-2222-3333", mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					One(ctx, dynamo.LpaKey("123"), dynamo.DonorKey("456"), mock.Anything).
+					Return(nil).
+					SetData(donordata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.LpaOwnerKey(dynamo.DonorKey("456")),
+						Tasks: donordata.Tasks{ConfirmYourIdentity: task.IdentityStatePending},
+					})
+
+				return c
+			},
+		},
+		"certificateProvider": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(ctx, "M-1111-2222-3333", mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					OneByPartialSK(ctx, dynamo.LpaKey("123"), dynamo.CertificateProviderKey(""), mock.Anything).
+					Return(nil).
+					SetData(&certificateproviderdata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.CertificateProviderKey("789"),
+						Tasks: certificateproviderdata.Tasks{ConfirmYourIdentity: task.IdentityStatePending},
+					})
+
+				return c
+			},
+		},
+	}
+
+	for actorType, tc := range testcases {
+		t.Run(actorType, func(t *testing.T) {
+			event := &events.CloudWatchEvent{
+				DetailType: "immaterial-change-confirmed",
+				Detail:     json.RawMessage(fmt.Sprintf(`{"uid":"M-1111-2222-3333","actorUID":"740e5834-3a29-46b4-9a6f-16142fde533a","actorType":"%s"}`, actorType)),
+			}
+
+			err := handleChangeConfirmed(ctx, tc.setupDynamoClient(), event, testNowFn, false)
+
+			assert.Nil(t, err)
+		})
+	}
+}
+
+func TestHandleChangeConfirmedWhenDynamoClientPutError(t *testing.T) {
+	testcases := map[string]struct {
+		setupDynamoClient func() *mockDynamodbClient
+	}{
+		"donor": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(mock.Anything, mock.Anything, mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					One(mock.Anything, mock.Anything, mock.Anything, mock.Anything).
+					Return(nil).
+					SetData(donordata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.LpaOwnerKey(dynamo.DonorKey("456")),
+						Tasks: donordata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+					})
+				c.EXPECT().
+					Put(mock.Anything, mock.Anything).
+					Return(expectedError)
+
+				return c
+			},
+		},
+		"certificateProvider": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(mock.Anything, mock.Anything, mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					OneByPartialSK(mock.Anything, mock.Anything, mock.Anything, mock.Anything).
+					Return(nil).
+					SetData(&certificateproviderdata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.CertificateProviderKey("789"),
+						Tasks: certificateproviderdata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+					})
+				c.EXPECT().
+					Put(ctx, mock.Anything).
+					Return(expectedError)
+
+				return c
+			},
+		},
+	}
+
+	for actorType, tc := range testcases {
+		t.Run(actorType, func(t *testing.T) {
+			event := &events.CloudWatchEvent{
+				DetailType: "immaterial-change-confirmed",
+				Detail:     json.RawMessage(fmt.Sprintf(`{"uid":"M-1111-2222-3333","actorUID":"740e5834-3a29-46b4-9a6f-16142fde533a","actorType":"%s"}`, actorType)),
+			}
+
+			err := handleChangeConfirmed(ctx, tc.setupDynamoClient(), event, testNowFn, false)
+
+			assert.ErrorIs(t, err, expectedError)
+		})
+	}
+}
+
+func TestHandleImmaterialChangeConfirmedWhenUnexpectedActorType(t *testing.T) {
+	event := &events.CloudWatchEvent{
+		DetailType: "immaterial-change-confirmed",
+		Detail:     json.RawMessage(`{"uid":"M-1111-2222-3333","actorUID":"740e5834-3a29-46b4-9a6f-16142fde533a","actorType":"attorney"}`),
+	}
+
+	err := handleChangeConfirmed(ctx, nil, event, testNowFn, false)
+
+	assert.ErrorContains(t, err, "invalid actorType, got attorney, want donor or certificateProvider")
+}
+
+func TestHandleMaterialChangeConfirmed(t *testing.T) {
+	testcases := map[string]struct {
+		setupDynamoClient func() *mockDynamodbClient
+	}{
+		"donor": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				updated := &donordata.Provided{
+					PK:                        dynamo.LpaKey("123"),
+					SK:                        dynamo.LpaOwnerKey(dynamo.DonorKey("456")),
+					Tasks:                     donordata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+					UpdatedAt:                 testNow,
+					MaterialChangeConfirmedAt: testNow,
+				}
+				updated.UpdateHash()
+
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(ctx, "M-1111-2222-3333", mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					One(ctx, dynamo.LpaKey("123"), dynamo.DonorKey("456"), mock.Anything).
+					Return(nil).
+					SetData(donordata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.LpaOwnerKey(dynamo.DonorKey("456")),
+						Tasks: donordata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+					})
+				c.EXPECT().
+					Put(ctx, updated).
+					Return(nil)
+
+				return c
+			},
+		},
+		"certificateProvider": {
+			setupDynamoClient: func() *mockDynamodbClient {
+				c := newMockDynamodbClient(t)
+				c.EXPECT().
+					OneByUID(ctx, "M-1111-2222-3333", mock.Anything).
+					Return(nil).
+					SetData(dynamo.Keys{PK: dynamo.LpaKey("123"), SK: dynamo.DonorKey("456")})
+				c.EXPECT().
+					OneByPartialSK(ctx, dynamo.LpaKey("123"), dynamo.CertificateProviderKey(""), mock.Anything).
+					Return(nil).
+					SetData(&certificateproviderdata.Provided{
+						PK:    dynamo.LpaKey("123"),
+						SK:    dynamo.CertificateProviderKey("789"),
+						Tasks: certificateproviderdata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+					})
+				c.EXPECT().
+					Put(ctx, &certificateproviderdata.Provided{
+						PK:                        dynamo.LpaKey("123"),
+						SK:                        dynamo.CertificateProviderKey("789"),
+						Tasks:                     certificateproviderdata.Tasks{ConfirmYourIdentity: task.IdentityStateProblem},
+						UpdatedAt:                 testNow,
+						MaterialChangeConfirmedAt: testNow,
+					}).
+					Return(nil)
+
+				return c
+			},
+		},
+	}
+
+	for actorType, tc := range testcases {
+		t.Run(actorType, func(t *testing.T) {
+			event := &events.CloudWatchEvent{
+				DetailType: "material-change-confirmed",
+				Detail:     json.RawMessage(fmt.Sprintf(`{"uid":"M-1111-2222-3333","actorUID":"740e5834-3a29-46b4-9a6f-16142fde533a","actorType":"%s"}`, actorType)),
+			}
+
+			factory := newMockFactory(t)
+			factory.EXPECT().
+				DynamoClient().
+				Return(tc.setupDynamoClient())
+			factory.EXPECT().
+				Now().
+				Return(testNowFn)
+
+			handler := &siriusEventHandler{}
+			err := handler.Handle(ctx, factory, event)
+
+			assert.Nil(t, err)
+		})
+	}
+}
diff --git a/internal/certificateprovider/certificateproviderdata/provided.go b/internal/certificateprovider/certificateproviderdata/provided.go
index 0566002a5f..d9c677695f 100644
--- a/internal/certificateprovider/certificateproviderdata/provided.go
+++ b/internal/certificateprovider/certificateproviderdata/provided.go
@@ -38,6 +38,10 @@ type Provided struct {
 	ContactLanguagePreference localize.Lang
 	// Email is the email address returned from OneLogin when the certificate provider logged in
 	Email string
+
+	// MaterialChangeConfirmedAt records when a material change to LPA data was
+	// confirmed by a caseworker
+	MaterialChangeConfirmedAt time.Time `checkhash:"-"`
 }
 
 func (c *Provided) CertificateProviderIdentityConfirmed(firstNames, lastName string) bool {
diff --git a/internal/donor/donordata/provided.go b/internal/donor/donordata/provided.go
index a231f63355..383300d43c 100644
--- a/internal/donor/donordata/provided.go
+++ b/internal/donor/donordata/provided.go
@@ -200,12 +200,20 @@ type Provided struct {
 	// donor informing them of a problem.
 	PriorityCorrespondenceSentAt time.Time `checkhash:"-"`
 
+	// MaterialChangeConfirmedAt records when a material change to LPA data was
+	// confirmed by a caseworker
+	MaterialChangeConfirmedAt time.Time `checkhash:"-"`
+
 	// HasSeenSuccessfulVouchBanner records if the donor has seen the progress tracker successful vouch banner
 	HasSeenSuccessfulVouchBanner bool `checkhash:"-"`
 
 	// HasSeenReducedFeeApprovalNotification records if the donor has seen the progress tracker exemption/remission fee approved banner
 	HasSeenReducedFeeApprovalNotification bool `checkhash:"-"`
 
+	// HasSeenIdentityMismatchResolvedNotification records if the donor has seen the progress tracker identity
+	// confirmed banner
+	HasSeenIdentityMismatchResolvedNotification bool `checkhash:"-"`
+
 	// ReducedFeeApprovedAt records when an exemption/remission was approved.
 	ReducedFeeApprovedAt time.Time `checkhash:"-"`
 
diff --git a/internal/donor/donordata/provided_test.go b/internal/donor/donordata/provided_test.go
index af540bf350..c40d3151bb 100644
--- a/internal/donor/donordata/provided_test.go
+++ b/internal/donor/donordata/provided_test.go
@@ -217,14 +217,14 @@ func TestGenerateHash(t *testing.T) {
 	}
 
 	// DO change this value to match the updates
-	const modified uint64 = 0xd6e3407c0de9ebec
+	const modified uint64 = 0xd75cf269f55b2bb0
 
 	// DO NOT change these initial hash values. If a field has been added/removed
 	// you will need to handle the version gracefully by modifying
 	// (*Provided).HashInclude and adding another testcase for the new
 	// version.
 	testcases := map[uint8]uint64{
-		0: 0x424aa066b6c0f772,
+		0: 0x5dc4d95782e4dcdc,
 	}
 
 	for version, initial := range testcases {
diff --git a/internal/donor/donorpage/progress.go b/internal/donor/donorpage/progress.go
index 93410cbb62..28234f77af 100644
--- a/internal/donor/donorpage/progress.go
+++ b/internal/donor/donorpage/progress.go
@@ -253,6 +253,14 @@ func Progress(tmpl template.Template, lpaStoreResolvingService LpaStoreResolving
 			data.addInfo("confirmationOfIdentityPending", "youDoNotNeedToTakeAnyAction")
 		}
 
+		if donor.Tasks.ConfirmYourIdentity.IsCompleted() &&
+			donor.ContinueWithMismatchedIdentity &&
+			!donor.HasSeenIdentityMismatchResolvedNotification {
+			data.addSuccess("yourIdentityHadBeenConfirmed", "youDoNotNeedToTakeAnyAction")
+
+			donor.HasSeenIdentityMismatchResolvedNotification = true
+		}
+
 		if !lpa.Status.IsRegistered() &&
 			!donor.PriorityCorrespondenceSentAt.IsZero() {
 			data.addInfo(
@@ -264,6 +272,18 @@ func Progress(tmpl template.Template, lpaStoreResolvingService LpaStoreResolving
 			)
 		}
 
+		if donor.Tasks.ConfirmYourIdentity.IsProblem() &&
+			donor.ContinueWithMismatchedIdentity &&
+			!donor.MaterialChangeConfirmedAt.IsZero() {
+			data.addInfo(
+				"yourLPACannotBeRegisteredByOPG",
+				appData.Localizer.Format(
+					"weContactedYouOnWithGuidanceAboutWhatToDoNext",
+					map[string]any{"ContactedDate": appData.Localizer.FormatDate(donor.MaterialChangeConfirmedAt)},
+				),
+			)
+		}
+
 		if err := donorStore.Put(r.Context(), donor); err != nil {
 			return fmt.Errorf("failed to update donor: %v", err)
 		}
diff --git a/internal/donor/donorpage/progress_test.go b/internal/donor/donorpage/progress_test.go
index fe1c059f09..ff2a0a91da 100644
--- a/internal/donor/donorpage/progress_test.go
+++ b/internal/donor/donorpage/progress_test.go
@@ -666,6 +666,67 @@ func TestGetProgress(t *testing.T) {
 			setupCertificateProviderStore: certificateProviderStoreNotFound,
 			setupDonorStore:               donorStoreNoUpdate,
 		},
+		"identity mismatch resolved": {
+			donor: &donordata.Provided{
+				ContinueWithMismatchedIdentity: true,
+				IdentityUserData:               identity.UserData{Status: identity.StatusConfirmed},
+				Tasks: donordata.Tasks{
+					ConfirmYourIdentity: task.IdentityStateCompleted,
+				},
+			},
+			lpa:                           &lpadata.Lpa{},
+			setupCertificateProviderStore: certificateProviderStoreNotFound,
+			successNotifications: []progressNotification{
+				{Heading: "yourIdentityHadBeenConfirmed", Body: "youDoNotNeedToTakeAnyAction"},
+			},
+			setupDonorStore: func(_ *testing.T, s *mockDonorStore) {
+				s.EXPECT().
+					Put(mock.Anything, &donordata.Provided{
+						ContinueWithMismatchedIdentity: true,
+						IdentityUserData:               identity.UserData{Status: identity.StatusConfirmed},
+						Tasks: donordata.Tasks{
+							ConfirmYourIdentity: task.IdentityStateCompleted,
+						},
+						HasSeenIdentityMismatchResolvedNotification: true,
+					}).
+					Return(nil)
+			},
+		},
+		"identity mismatch resolved when already seen": {
+			donor: &donordata.Provided{
+				ContinueWithMismatchedIdentity: true,
+				IdentityUserData:               identity.UserData{Status: identity.StatusConfirmed},
+				Tasks: donordata.Tasks{
+					ConfirmYourIdentity: task.IdentityStateCompleted,
+				},
+				HasSeenIdentityMismatchResolvedNotification: true,
+			},
+			lpa:                           &lpadata.Lpa{},
+			setupCertificateProviderStore: certificateProviderStoreNotFound,
+			setupDonorStore:               donorStoreNoUpdate,
+		},
+		"identity mismatch material change confirmed": {
+			donor: &donordata.Provided{
+				ContinueWithMismatchedIdentity: true,
+				IdentityUserData:               identity.UserData{Status: identity.StatusConfirmed},
+				Tasks: donordata.Tasks{
+					ConfirmYourIdentity: task.IdentityStateProblem,
+				},
+				MaterialChangeConfirmedAt: testNow,
+			},
+			lpa:                           &lpadata.Lpa{},
+			setupCertificateProviderStore: certificateProviderStoreNotFound,
+			setupDonorStore:               donorStoreNoUpdate,
+			infoNotifications: []progressNotification{
+				{Heading: "yourLPACannotBeRegisteredByOPG", Body: "B"},
+			},
+			setupLocalizer: func(t *testing.T) *mockLocalizer {
+				l := newMockLocalizer(t)
+				l.EXPECT().Format("weContactedYouOnWithGuidanceAboutWhatToDoNext", map[string]any{"ContactedDate": "translated date"}).Return("B")
+				l.EXPECT().FormatDate(testNow).Return("translated date")
+				return l
+			},
+		},
 	}
 
 	for name, tc := range testCases {
diff --git a/lang/cy.json b/lang/cy.json
index ac6a68557c..ba1751a5a9 100644
--- a/lang/cy.json
+++ b/lang/cy.json
@@ -1582,5 +1582,6 @@
     "and:en": "Welsh",
     "and:cy": "Welsh",
     "donorHasChosenToHaveTheirLpaRegisteredInContent": "<div class=\"govuk-notification-banner__content\"><p class=\"govuk-notification-banner__heading\">Welsh {{.DonorFullName}} {{.InSelected}}</p><p class=\"govuk-body\">{{.BetweenSelected}} {{.AndUnselected}}.</p><p class=\"govuk-body\">{{.DonorFullName}} {{.InSelected}}</p></div>",
-    "donorHasChosenToHaveTheirLpaRegisteredInAttorneyContent": "<div class=\"govuk-notification-banner__content\"><p class=\"govuk-notification-banner__heading\">Welsh {{.DonorFullName}} {{.InSelected}}</p><p class=\"govuk-body\">{{.DonorFullName}} {{.InSelected}}</p></div>"
+    "donorHasChosenToHaveTheirLpaRegisteredInAttorneyContent": "<div class=\"govuk-notification-banner__content\"><p class=\"govuk-notification-banner__heading\">Welsh {{.DonorFullName}} {{.InSelected}}</p><p class=\"govuk-body\">{{.DonorFullName}} {{.InSelected}}</p></div>",
+    "yourIdentityHadBeenConfirmed": "Welsh"
 }
diff --git a/lang/en.json b/lang/en.json
index aa1500f50a..5814984658 100644
--- a/lang/en.json
+++ b/lang/en.json
@@ -1478,5 +1478,6 @@
     "and:en": "and English",
     "and:cy": "and Welsh",
     "donorHasChosenToHaveTheirLpaRegisteredInContent": "<div class=\"govuk-notification-banner__content\"><p class=\"govuk-notification-banner__heading\">{{.DonorFullName}} has chosen to have their LPA registered {{.InSelected}}</p><p class=\"govuk-body\">When reading the LPA, you can switch {{.BetweenSelected}} {{.AndUnselected}}.</p><p class=\"govuk-body\">Bear in mind that any restrictions and conditions {{.DonorFullName}} has written {{.InSelected}} will not be translated.</p></div>",
-    "donorHasChosenToHaveTheirLpaRegisteredInAttorneyContent": "<div class=\"govuk-notification-banner__content\"><p class=\"govuk-notification-banner__heading\">{{.DonorFullName}} has chosen to have their LPA registered {{.InSelected}}. This is a translation.</p><p class=\"govuk-body\">Bear in mind that any restrictions and conditions {{.DonorFullName}} has written {{.InSelected}} will not be translated.</p></div>"
+    "donorHasChosenToHaveTheirLpaRegisteredInAttorneyContent": "<div class=\"govuk-notification-banner__content\"><p class=\"govuk-notification-banner__heading\">{{.DonorFullName}} has chosen to have their LPA registered {{.InSelected}}. This is a translation.</p><p class=\"govuk-body\">Bear in mind that any restrictions and conditions {{.DonorFullName}} has written {{.InSelected}} will not be translated.</p></div>",
+    "yourIdentityHadBeenConfirmed": "Your identity has been confirmed"
 }