class RealmGame : RealmObject {
    ...
    var executablePath: String? = null
    ...
}

class RealmGame : RealmObject {
    ...
    var executablePaths: RealmSet<String> = realmSetOf()
    ...
}

private class MyMigration : AutomaticSchemaMigration {
    override fun migrate(migrationContext: AutomaticSchemaMigration.MigrationContext) {
        migrationContext.enumerate(RealmGame::class.simpleName!!) { oldObject: DynamicRealmObject, newObject: DynamicMutableRealmObject? ->
            newObject?.run {
                val executablePath: String? = oldObject.getNullableValue("executablePath")
                executablePath?.let {
                    set<RealmSet<String>>(
                        "executablePaths",
                        realmSetOf<String>(it)
                    )
                }
            }
        }
    }

}

Caused by: java.lang.IllegalArgumentException: Trying to access property 'RealmGame.executablePaths' as type: 'RealmSet<class io.realm.kotlin.internal.UnmanagedRealmSet>' but actual schema type is 'RealmSet<class kotlin.String>'
	at io.realm.kotlin.internal.RealmObjectHelper.checkPropertyType(RealmObjectHelper.kt:1230)
	at io.realm.kotlin.internal.RealmObjectHelper.dynamicGetSet$io_realm_kotlin_library(RealmObjectHelper.kt:965)
	at io.realm.kotlin.internal.RealmObjectHelper.dynamicGetSet$io_realm_kotlin_library$default(RealmObjectHelper.kt:957)
	at io.realm.kotlin.internal.RealmObjectHelper.dynamicSetValue$io_realm_kotlin_library(RealmObjectHelper.kt:1132)
	at io.realm.kotlin.internal.RealmObjectHelper.dynamicSetValue$io_realm_kotlin_library$default(RealmObjectHelper.kt:1028)
	at io.realm.kotlin.internal.dynamic.DynamicMutableRealmObjectImpl.set(DynamicMutableRealmObjectImpl.kt:134)
	at org.skynetsoftware.avnlauncher.data.database.MyMigration$migrate$1.invoke(DatabaseKoinModule.kt:32)
	at org.skynetsoftware.avnlauncher.data.database.MyMigration$migrate$1.invoke(DatabaseKoinModule.kt:28)
	at io.realm.kotlin.migration.AutomaticSchemaMigration$MigrationContext$DefaultImpls.enumerate(AutomaticSchemaMigration.kt:112)
	at io.realm.kotlin.internal.ConfigurationImpl$migrationCallback$1$1$1.enumerate(ConfigurationImpl.kt:172)
	at org.skynetsoftware.avnlauncher.data.database.MyMigration.migrate(DatabaseKoinModule.kt:28)
	at io.realm.kotlin.internal.ConfigurationImpl.lambda$3$lambda$2(ConfigurationImpl.kt:172)
	at io.realm.kotlin.internal.interop.realmcJNI.realm_open(Native Method)
	at io.realm.kotlin.internal.interop.realmc.realm_open(realmc.java:426)
	at io.realm.kotlin.internal.interop.RealmInterop.realm_open(RealmInterop.kt:235)
	at io.realm.kotlin.internal.ConfigurationImpl$openRealm$2.invoke(ConfigurationImpl.kt:115)
	at io.realm.kotlin.internal.ConfigurationImpl$openRealm$2.invoke(ConfigurationImpl.kt:114)
	at io.realm.kotlin.internal.interop.NativePointerKt.use(NativePointer.kt:53)
	at io.realm.kotlin.internal.ConfigurationImpl.openRealm$suspendImpl(ConfigurationImpl.kt:114)
	at io.realm.kotlin.internal.ConfigurationImpl.openRealm(ConfigurationImpl.kt)
	at io.realm.kotlin.internal.RealmImpl$1.invokeSuspend(RealmImpl.kt:130)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:108)
	at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:280)
	at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:85)
	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59)
	at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
	at io.realm.kotlin.internal.platform.CoroutineUtilsSharedJvmKt.runBlocking(CoroutineUtilsSharedJvm.kt:22)
	at io.realm.kotlin.internal.platform.CoroutineUtilsSharedJvmKt.runBlocking$default(CoroutineUtilsSharedJvm.kt:21)
	at io.realm.kotlin.internal.RealmImpl.<init>(RealmImpl.kt:112)
	at io.realm.kotlin.internal.RealmImpl.<init>(RealmImpl.kt)
	at io.realm.kotlin.internal.RealmImpl$Companion.create$io_realm_kotlin_library(RealmImpl.kt:308)
	at io.realm.kotlin.Realm$Companion.open(Realm.kt:83)
	at org.skynetsoftware.avnlauncher.data.database.DatabaseKoinModuleKt$databaseKoinModule$1$1.invoke(DatabaseKoinModule.kt:22)
	at org.skynetsoftware.avnlauncher.data.database.DatabaseKoinModuleKt$databaseKoinModule$1$1.invoke(DatabaseKoinModule.kt:17)
	at org.koin.core.instance.InstanceFactory.create(InstanceFactory.kt:50)
	... 37 more