val config = RealmConfiguration.Builder() .schemaVersion(1) .deleteRealmIfMigrationNeeded() .migration(MyMigration()) .build() Realm.setDefaultConfiguration(config)

You can't use

deleteRealmIfMigrationNeeded()

and

migration()

at the same time. But this is more a Realm question, rather than Kotlin

I'm agree with @mgaetan89 is more related with Realm, and I misunderstood the question, I just believe you want to migrate code to Kotlin, for that reason I sent you a link with Realm Kotlin example.

I already made it work

use

deleteRealmIfMigrationNeeded

just in case if you don't want to make a Realm Migration Schema

ok tnx @budioktaviyan