diff --git a/database/database.go b/database/database.go
index 47d31794..555da5f7 100644
--- a/database/database.go
+++ b/database/database.go
@@ -545,7 +545,7 @@ func (s *DatabaseService) DeleteExecutionPayloads(idFirst, idLast uint64) error
 }
 
 func (s *DatabaseService) InsertBuilderDemotion(submitBlockRequest *spec.VersionedSubmitBlockRequest, simError error) error {
-	_submitBlockRequest, err := json.Marshal(submitBlockRequest)
+	_submitBlockRequest, err := json.Marshal(submitBlockRequest.Capella)
 	if err != nil {
 		return err
 	}
@@ -578,7 +578,7 @@ func (s *DatabaseService) InsertBuilderDemotion(submitBlockRequest *spec.Version
 }
 
 func (s *DatabaseService) UpdateBuilderDemotion(trace *common.BidTraceV2, signedBlock *consensusspec.VersionedSignedBeaconBlock, signedRegistration *types.SignedValidatorRegistration) error {
-	_signedBeaconBlock, err := json.Marshal(signedBlock)
+	_signedBeaconBlock, err := json.Marshal(signedBlock.Capella)
 	if err != nil {
 		return err
 	}
diff --git a/services/api/optimistic_test.go b/services/api/optimistic_test.go
index 9ff1e5c2..6cdcc489 100644
--- a/services/api/optimistic_test.go
+++ b/services/api/optimistic_test.go
@@ -144,7 +144,7 @@ func runOptimisticBlockSubmission(t *testing.T, opts blockRequestOpts, simErr er
 	}
 
 	req := common.TestBuilderSubmitBlockRequest(opts.secretkey, getTestBidTrace(opts.pubkey, opts.blockValue))
-	rr := backend.request(http.MethodPost, pathSubmitNewBlock, &req)
+	rr := backend.request(http.MethodPost, pathSubmitNewBlock, req.Capella)
 
 	// Let updates happen async.
 	time.Sleep(100 * time.Millisecond)
diff --git a/services/api/service.go b/services/api/service.go
index 717d5551..27d559ca 100644
--- a/services/api/service.go
+++ b/services/api/service.go
@@ -19,7 +19,7 @@ import (
 	"strings"
 	"sync"
 	"time"
-
+	consensusspec "github.com/attestantio/go-eth2-client/spec"
 	"github.com/NYTimes/gziphandler"
 	builderCapella "github.com/attestantio/go-builder-client/api/capella"
 	"github.com/attestantio/go-builder-client/spec"
@@ -1590,18 +1590,20 @@ func (api *RelayAPI) handleSubmitNewBlock(w http.ResponseWriter, req *http.Reque
 		return
 	}
 
-	payload := new(spec.VersionedSubmitBlockRequest)
+	payload := &spec.VersionedSubmitBlockRequest{
+		Version: consensusspec.DataVersionCapella,
+	}
+	payload.Capella = new(builderCapella.SubmitBlockRequest)
 
 	// Check for SSZ encoding
 	contentType := req.Header.Get("Content-Type")
 	if contentType == "application/octet-stream" {
 		log = log.WithField("reqContentType", "ssz")
-		payload.Capella = new(builderCapella.SubmitBlockRequest)
 		if err = payload.Capella.UnmarshalSSZ(requestPayloadBytes); err != nil {
 			log.WithError(err).Warn("could not decode payload - SSZ")
 
 			// SSZ decoding failed. try JSON as fallback (some builders used octet-stream for json before)
-			if err2 := json.Unmarshal(requestPayloadBytes, payload); err2 != nil {
+			if err2 := json.Unmarshal(requestPayloadBytes, payload.Capella); err2 != nil {
 				log.WithError(fmt.Errorf("%w / %w", err, err2)).Warn("could not decode payload - SSZ or JSON")
 				api.RespondError(w, http.StatusBadRequest, err.Error())
 				return
@@ -1612,7 +1614,7 @@ func (api *RelayAPI) handleSubmitNewBlock(w http.ResponseWriter, req *http.Reque
 		}
 	} else {
 		log = log.WithField("reqContentType", "json")
-		if err := json.Unmarshal(requestPayloadBytes, payload); err != nil {
+		if err := json.Unmarshal(requestPayloadBytes, payload.Capella); err != nil {
 			log.WithError(err).Warn("could not decode payload - JSON")
 			api.RespondError(w, http.StatusBadRequest, err.Error())
 			return
@@ -1766,6 +1768,7 @@ func (api *RelayAPI) handleSubmitNewBlock(w http.ResponseWriter, req *http.Reque
 	// Verify the signature
 	log = log.WithField("timestampBeforeSignatureCheck", time.Now().UTC().UnixMilli())
 	signature := submission.Signature
+	fmt.Println(submission.BidTrace.String())
 	ok, err = boostTypes.VerifySignature(submission.BidTrace, api.opts.EthNetDetails.DomainBuilder, builderPubkey[:], signature[:])
 	log = log.WithField("timestampAfterSignatureCheck", time.Now().UTC().UnixMilli())
 	if err != nil {
diff --git a/services/api/service_test.go b/services/api/service_test.go
index 370d31a3..f55ed5e7 100644
--- a/services/api/service_test.go
+++ b/services/api/service_test.go
@@ -382,7 +382,8 @@ func TestBuilderSubmitBlockSSZ(t *testing.T) {
 	requestPayloadJSONBytes := common.LoadGzippedBytes(t, "../../testdata/submitBlockPayloadCapella_Goerli.json.gz")
 
 	req := new(spec.VersionedSubmitBlockRequest)
-	err := json.Unmarshal(requestPayloadJSONBytes, &req)
+	req.Capella = new(builderCapella.SubmitBlockRequest)
+	err := json.Unmarshal(requestPayloadJSONBytes, req.Capella)
 	require.NoError(t, err)
 
 	reqSSZ, err := req.Capella.MarshalSSZ()
@@ -436,9 +437,10 @@ func TestBuilderSubmitBlock(t *testing.T) {
 
 	// Prepare the request payload
 	req := new(spec.VersionedSubmitBlockRequest)
+	req.Capella = new(builderCapella.SubmitBlockRequest)
 	requestPayloadJSONBytes := common.LoadGzippedBytes(t, payloadJSONFilename)
 	require.NoError(t, err)
-	err = json.Unmarshal(requestPayloadJSONBytes, &req)
+	err = json.Unmarshal(requestPayloadJSONBytes, req.Capella)
 	require.NoError(t, err)
 
 	// Update