diff --git a/app/upgrade.go b/app/upgrade.go
index 21308195..9279a0db 100644
--- a/app/upgrade.go
+++ b/app/upgrade.go
@@ -7,7 +7,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/types/module"
 )
 
-const upgradeName = "0.6.2"
+const upgradeName = "0.6.4"
 
 // RegisterUpgradeHandlers returns upgrade handlers
 func (app *InitiaApp) RegisterUpgradeHandlers(cfg module.Configurator) {
diff --git a/x/ibc-hooks/move-hooks/message.go b/x/ibc-hooks/move-hooks/message.go
index 1eb161ef..5c16b27c 100644
--- a/x/ibc-hooks/move-hooks/message.go
+++ b/x/ibc-hooks/move-hooks/message.go
@@ -1,6 +1,8 @@
 package move_hooks
 
 import (
+	"encoding/json"
+
 	movetypes "github.com/initia-labs/initia/x/move/types"
 )
 
@@ -50,3 +52,45 @@ type HookData struct {
 	// sender chain.
 	AsyncCallback *AsyncCallback `json:"async_callback,omitempty"`
 }
+
+// asyncCallback is same as AsyncCallback.
+type asyncCallback struct {
+	// callback id should be issued form the executor contract
+	Id            uint64 `json:"id"`
+	ModuleAddress string `json:"module_address"`
+	ModuleName    string `json:"module_name"`
+}
+
+// asyncCallbackStringID is same as AsyncCallback but
+// it has Id as string.
+type asyncCallbackStringID struct {
+	// callback id should be issued form the executor contract
+	Id            uint64 `json:"id,string"`
+	ModuleAddress string `json:"module_address"`
+	ModuleName    string `json:"module_name"`
+}
+
+// UnmarshalJSON implements the json unmarshaler interface.
+// custom unmarshaler is required because we have to handle
+// id as string and uint64.
+func (a *AsyncCallback) UnmarshalJSON(bz []byte) error {
+	var ac asyncCallback
+	err := json.Unmarshal(bz, &ac)
+	if err != nil {
+		var acStr asyncCallbackStringID
+		err := json.Unmarshal(bz, &acStr)
+		if err != nil {
+			return err
+		}
+
+		a.Id = acStr.Id
+		a.ModuleAddress = acStr.ModuleAddress
+		a.ModuleName = acStr.ModuleName
+		return nil
+	}
+
+	a.Id = ac.Id
+	a.ModuleAddress = ac.ModuleAddress
+	a.ModuleName = ac.ModuleName
+	return nil
+}
diff --git a/x/ibc-hooks/move-hooks/message_test.go b/x/ibc-hooks/move-hooks/message_test.go
new file mode 100644
index 00000000..199918d3
--- /dev/null
+++ b/x/ibc-hooks/move-hooks/message_test.go
@@ -0,0 +1,33 @@
+package move_hooks_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	movehooks "github.com/initia-labs/initia/x/ibc-hooks/move-hooks"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_Unmarshal_AsyncCallback(t *testing.T) {
+	var callback movehooks.AsyncCallback
+	err := json.Unmarshal([]byte(`{
+		"id": 99,
+		"module_address": "0x1",
+		"module_name": "Counter"
+	}`), &callback)
+	require.NoError(t, err)
+	require.Equal(t, movehooks.AsyncCallback{
+		Id:            99,
+		ModuleAddress: "0x1",
+		ModuleName:    "Counter",
+	}, callback)
+
+	var callbackStringID movehooks.AsyncCallback
+	err = json.Unmarshal([]byte(`{
+		"id": "99",
+		"module_address": "0x1",
+		"module_name": "Counter"
+	}`), &callbackStringID)
+	require.NoError(t, err)
+	require.Equal(t, callback, callbackStringID)
+}