if len(unknown) > 0 {
		return errors.Errorf("unknown configuration APIs: %#v", unknown)
	}

	return nil
}

// MigrateOldConfig migrates an old configuration from a byte slice into a new one (returned again as a byte slice).
// Only kubeadm kinds are migrated.
func MigrateOldConfig(oldConfig []byte, allowExperimental bool, mutators migrateMutators) ([]byte, error) {
	newConfig := [][]byte{}

	if mutators == nil {

			`, gvExperimental)),
			allowExperimental: false,
			expectErr:         true,
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			b, err := MigrateOldConfig([]byte(test.oldCfg), test.allowExperimental, defaultEmptyMigrateMutators())
			if test.expectErr {
				if err == nil {
					t.Fatalf("unexpected success:\n%s", b)
				}
			} else {
				if err != nil {

				return errors.New("the --old-config flag is mandatory")
			}

			oldCfgBytes, err := os.ReadFile(oldCfgPath)
			if err != nil {
				return err
			}

			outputBytes, err := configutil.MigrateOldConfig(oldCfgBytes, allowExperimental, nil)
			if err != nil {
				return err
			}

			if newCfgPath == "" {
				fmt.Fprint(out, string(outputBytes))
			} else {