Add Capella-Bellatrix bid compatibility to proposer version check

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_bellatrix.go

@@ -322,7 +322,7 @@ func (vs *Server) getPayloadHeaderFromBuilder(
 func validateBuilderSignature(signedBid builder.SignedBid) error {
 	d, err := signing.ComputeDomain(params.BeaconConfig().DomainApplicationBuilder,
 		nil, /* fork version */
-		nil /* genesis val root */)
+		nil  /* genesis val root */)
 	if err != nil {
 		return err
 	}
@@ -471,6 +471,11 @@ func isVersionCompatible(bidVersion, headBlockVersion int) bool {
 		return true
 	}
 
+	// Allow Capella bids for Bellatrix blocks - they have compatible formats
+	if bidVersion == version.Capella && headBlockVersion == version.Bellatrix {
+		return true
+	}
+
 	// For all other cases, require exact version match
 	return false
 }

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_bellatrix_test.go

@@ -1378,6 +1378,12 @@ func TestIsVersionCompatible(t *testing.T) {
 			headBlockVersion: version.Capella,
 			want:             false,
 		},
+		{
+			name:             "Capella bid with Bellatrix head block - Compatible",
+			bidVersion:       version.Capella,
+			headBlockVersion: version.Bellatrix,
+			want:             true,
+		},
 		{
 			name:             "Phase0 bid with Altair head block - Not compatible",
 			bidVersion:       version.Phase0,

changelog/ttsao_add-capella-bellatrix-compatibility.md

@@ -0,0 +1,3 @@
+### Fixed
+
+- Add Capella-Bellatrix bid compatibility to proposer version check