Cosmos Dev Series: Cosmos-SDK-based Blockchain Upgrade - x/foo module

module.go

package foo

// RegisterServices registers a GRPC query service to respond to the
// module-specific GRPC queries.
func (am AppModule) RegisterServices(cfg module.Configurator) {
    ...
    migrator := keeper.NewMigrator(am.keeper)
    
    // register v1 -> v2 migration
    if err := cfg.RegisterMigration(types.ModuleName, 1, migrator.Migrate1to2); err != nil {
        panic(fmt.Errorf("failed to migrate %s to v2: %w", types.ModuleName, err))
    }
}

// ConsensusVersion implements ConsensusVersion.
func (AppModule) ConsensusVersion() uint64 { 
    return 2 
}