diff --git a/beacon/versioned_beacon_state.go b/beacon/versioned_beacon_state.go
index 32841707..bbbb2eeb 100644
--- a/beacon/versioned_beacon_state.go
+++ b/beacon/versioned_beacon_state.go
@@ -82,14 +82,22 @@ func CreateVersionedState(state interface{}) (spec.VersionedBeaconState, error)
 
 func UnmarshalSSZVersionedBeaconState(data []byte) (*spec.VersionedBeaconState, error) {
 	beaconState := &spec.VersionedBeaconState{}
+	denebBeaconState := &deneb.BeaconState{}
 	// Try to unmarshal using Deneb
-	err := beaconState.Deneb.UnmarshalSSZ(data)
+	err := denebBeaconState.UnmarshalSSZ(data)
 	if err != nil {
 		// If Deneb fails, try Capella
-		err = beaconState.Capella.UnmarshalSSZ(data)
+		capellaBeaconState := &capella.BeaconState{}
+		err = capellaBeaconState.UnmarshalSSZ(data)
 		if err != nil {
 			return nil, err
+		} else {
+			beaconState.Capella = capellaBeaconState
+			beaconState.Version = spec.DataVersionCapella
 		}
+	} else {
+		beaconState.Deneb = denebBeaconState
+		beaconState.Version = spec.DataVersionDeneb
 	}
 
 	return beaconState, nil
@@ -97,10 +105,14 @@ func UnmarshalSSZVersionedBeaconState(data []byte) (*spec.VersionedBeaconState,
 
 func MarshalSSZVersionedBeaconState(beaconState spec.VersionedBeaconState) ([]byte, error) {
 	var data []byte
+	var err error
 	// Try to marshal using Deneb
-	data, err := beaconState.Deneb.MarshalSSZ()
-	if err != nil {
-		// If Deneb fails, try Capella
+	if beaconState.Version == spec.DataVersionDeneb {
+		data, err = beaconState.Deneb.MarshalSSZ()
+		if err != nil {
+			return nil, err
+		}
+	} else {
 		data, err = beaconState.Capella.MarshalSSZ()
 		if err != nil {
 			return nil, err
diff --git a/merkle_util_test.go b/merkle_util_test.go
index 5e370e1c..ba364842 100644
--- a/merkle_util_test.go
+++ b/merkle_util_test.go
@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"github.com/attestantio/go-eth2-client/spec"
+	"github.com/attestantio/go-eth2-client/spec/altair"
 	"github.com/attestantio/go-eth2-client/spec/capella"
 	"github.com/attestantio/go-eth2-client/spec/deneb"
 	"github.com/attestantio/go-eth2-client/spec/phase0"
@@ -250,6 +251,96 @@ func TestProveWithdrawals(t *testing.T) {
 	assert.True(t, flag, "Historical Summary Block Root Proof %v failed")
 }
 
+func TestUnmarshalSSZVersionedBeaconStateDeneb(t *testing.T) {
+	oracleStateBytes, err := oracleState.MarshalSSZ()
+	if err != nil {
+		fmt.Println("error", err)
+	}
+
+	versionedBeaconState, err := beacon.UnmarshalSSZVersionedBeaconState(oracleStateBytes)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBeaconState.Version, spec.DataVersionDeneb, "Version %v failed")
+
+	versionedBeaconStateBytes, err := versionedBeaconState.Deneb.MarshalSSZ()
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBeaconStateBytes, oracleStateBytes, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
+func TestUnmarshalSSZVersionedBeaconStateCapella(t *testing.T) {
+	var capellaState capella.BeaconState
+	capellaStateJSON, err := ParseJSONFileCapella("data/goerli_slot_6409723.json")
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	ParseCapellaBeaconStateFromJSON(*capellaStateJSON, &capellaState)
+
+	capellaStateBytes, err := capellaState.MarshalSSZ()
+	if err != nil {
+		fmt.Println("error", err)
+	}
+
+	versionedBeaconState, err := beacon.UnmarshalSSZVersionedBeaconState(capellaStateBytes)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBeaconState.Version, spec.DataVersionCapella, "Version %v failed")
+
+	versionedBeaconStateBytes, err := versionedBeaconState.Capella.MarshalSSZ()
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBeaconStateBytes, capellaStateBytes, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
+func TestMarshalSSZVersionedBeaconStateDeneb(t *testing.T) {
+	oracleStateBytes, err := oracleState.MarshalSSZ()
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	versionedBeaconState, err := beacon.CreateVersionedState(&oracleState)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+
+	versionedBeaconStateBytes, err := beacon.MarshalSSZVersionedBeaconState(versionedBeaconState)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBeaconStateBytes, oracleStateBytes, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
+func TestMarshalSSZVersionedBeaconStateCapella(t *testing.T) {
+	var capellaState capella.BeaconState
+	capellaStateJSON, err := ParseJSONFileCapella("data/goerli_slot_6409723.json")
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	ParseCapellaBeaconStateFromJSON(*capellaStateJSON, &capellaState)
+
+	capellaStateBytes, err := capellaState.MarshalSSZ()
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	versionedBeaconState, err := beacon.CreateVersionedState(&capellaState)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+
+	versionedBeaconStateBytes, err := beacon.MarshalSSZVersionedBeaconState(versionedBeaconState)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBeaconStateBytes, capellaStateBytes, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
 func TestGenerateWithdrawalCredentialsProof(t *testing.T) {
 
 	// picking up one random validator index
@@ -270,6 +361,64 @@ func TestGenerateWithdrawalCredentialsProof(t *testing.T) {
 	assert.True(t, flag, "Proof %v failed")
 }
 
+func TestCreateVersionedSignedBlockDeneb(t *testing.T) {
+	block := deneb.BeaconBlock{}
+	versionedBlock, err := beacon.CreateVersionedSignedBlock(block)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBlock.Version, spec.DataVersionDeneb, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
+func TestCreateVersionedSignedBlockCapella(t *testing.T) {
+	block := capella.BeaconBlock{}
+	versionedBlock, err := beacon.CreateVersionedSignedBlock(block)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedBlock.Version, spec.DataVersionCapella, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
+func TestCreateVersionedSignedBlockAltair(t *testing.T) {
+	block := altair.BeaconBlock{}
+	_, err := beacon.CreateVersionedSignedBlock(block)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.NotNil(t, err, "error %v was nil")
+}
+
+func TestCreateVersionedBeaconStateDeneb(t *testing.T) {
+	oracleState := deneb.BeaconState{}
+	versionedState, err := beacon.CreateVersionedState(&oracleState)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedState.Version, spec.DataVersionDeneb, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
+func TestCreateVersionedBeaconStateCapella(t *testing.T) {
+	state := capella.BeaconState{}
+	versionedState, err := beacon.CreateVersionedState(&state)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.Equal(t, versionedState.Version, spec.DataVersionCapella, "Version %v failed")
+	assert.Nil(t, err, "Error %v failed")
+}
+
+func TestCreateVersionedBeaconStateAltair(t *testing.T) {
+	state := altair.BeaconState{}
+	_, err := beacon.CreateVersionedState(&state)
+	if err != nil {
+		fmt.Println("error", err)
+	}
+	assert.NotNil(t, err, "error %v was nil")
+}
+
 func TestProveValidatorBalanceAgainstValidatorBalanceList(t *testing.T) {
 
 	validatorIndex := phase0.ValidatorIndex(REPOINTED_VALIDATOR_INDEX)