diff --git a/x/mint/keeper/migrations.go b/x/mint/keeper/migrations.go
index 9b5879ee..8ed612a9 100644
--- a/x/mint/keeper/migrations.go
+++ b/x/mint/keeper/migrations.go
@@ -3,22 +3,19 @@ package keeper
 import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 
-	"github.com/okp4/okp4d/x/mint/exported"
 	v3 "github.com/okp4/okp4d/x/mint/migrations/v3"
 )
 
 type Migrator struct {
-	keeper         Keeper
-	legacySubspace exported.Subspace
+	keeper Keeper
 }
 
-func NewMigrator(keeper Keeper, legacySubspace exported.Subspace) Migrator {
+func NewMigrator(keeper Keeper) Migrator {
 	return Migrator{
-		keeper:         keeper,
-		legacySubspace: legacySubspace,
+		keeper: keeper,
 	}
 }
 
 func (m Migrator) Migrate2to3(ctx sdk.Context) error {
-	return v3.MigrateStore(ctx, m.keeper.storeKey, m.keeper.cdc, m.legacySubspace)
+	return v3.MigrateStore(ctx, ctx.KVStore(m.keeper.storeKey), m.keeper.cdc)
 }
diff --git a/x/mint/migrations/v3/migrations.go b/x/mint/migrations/v3/migrations.go
index 338c8f1d..49c15f8f 100644
--- a/x/mint/migrations/v3/migrations.go
+++ b/x/mint/migrations/v3/migrations.go
@@ -2,18 +2,16 @@ package v3
 
 import (
 	"github.com/cosmos/cosmos-sdk/codec"
-	storetypes "github.com/cosmos/cosmos-sdk/store/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-
-	"github.com/okp4/okp4d/x/mint/exported"
+	"github.com/okp4/okp4d/x/mint/types"
 )
 
 // MigrateStore migrates the x/mint module state from the consensus version 2 to
 // version 3.
+// This version include new/deleted parameters in store.
 func MigrateStore(ctx sdk.Context,
-	storeKey storetypes.StoreKey,
+	store sdk.KVStore,
 	cdc codec.BinaryCodec,
-	legacySubspace exported.Subspace,
 ) error {
 	logger := ctx.Logger().
 		With("module", "mint").
@@ -23,7 +21,13 @@ func MigrateStore(ctx sdk.Context,
 
 	logger.Debug("migrate mint params")
 
-	// TODO:
+	newParams := types.DefaultParams()
+
+	bz, err := cdc.Marshal(&newParams)
+	if err != nil {
+		return err
+	}
+	store.Set(types.ParamsKey, bz)
 
 	logger.Debug("module migration done")
 
diff --git a/x/mint/module.go b/x/mint/module.go
index 2cd8e541..b9d133d9 100644
--- a/x/mint/module.go
+++ b/x/mint/module.go
@@ -18,7 +18,6 @@ import (
 	simtypes "github.com/cosmos/cosmos-sdk/types/simulation"
 
 	"github.com/okp4/okp4d/x/mint/client/cli"
-	"github.com/okp4/okp4d/x/mint/exported"
 	"github.com/okp4/okp4d/x/mint/keeper"
 	"github.com/okp4/okp4d/x/mint/simulation"
 	"github.com/okp4/okp4d/x/mint/types"
@@ -87,17 +86,14 @@ type AppModule struct {
 
 	keeper     keeper.Keeper
 	authKeeper types.AccountKeeper
-	// legacySubspace is used principally for migration
-	legacySubspace exported.Subspace
 }
 
 // NewAppModule creates a new AppModule object.
-func NewAppModule(cdc codec.Codec, keeper keeper.Keeper, ak types.AccountKeeper, legacySubspace exported.Subspace) AppModule {
+func NewAppModule(cdc codec.Codec, keeper keeper.Keeper, ak types.AccountKeeper) AppModule {
 	return AppModule{
 		AppModuleBasic: AppModuleBasic{cdc: cdc},
 		keeper:         keeper,
 		authKeeper:     ak,
-		legacySubspace: legacySubspace,
 	}
 }
 
@@ -115,7 +111,7 @@ func (am AppModule) RegisterServices(cfg module.Configurator) {
 	types.RegisterMsgServer(cfg.MsgServer(), keeper.NewMsgServerImpl(am.keeper))
 	types.RegisterQueryServer(cfg.QueryServer(), am.keeper)
 
-	migrator := keeper.NewMigrator(am.keeper, am.legacySubspace)
+	migrator := keeper.NewMigrator(am.keeper)
 
 	migrations := []struct {
 		fromVersion uint64