public static boolean legacyFolderNeedsToBeMigrated(@StringRes final int newPrefKey) {
        for (String legacyKey : getLegacyPreferenceKeysFor(newPrefKey)) {
            final String value = getStringDirect(legacyKey, null);
            if (value != null && !value.startsWith(LEGACY_UNUSED_MARKER)) {
                return true;
            }
        }
        return false;
    }
checks whether legacy folder needs to be migrated
(legacy value is set and not yet migrated)
(used by the installation / migration wizard)
main/src/main/java/cgeo/geocaching/settings/Settings.java