@NonNull
    public static MapDownloaderOpenAndroMaps getInstance() {
        return INSTANCE;
    }
Return an updated path string, reflecting folder structure changes between
OAM v4 maps and OAM v5 maps
- last segment in path is now completely lower-case
- "mapsV4" part has changed to "mapsV5"

@param oldPath folder name (without trailing '/', and without filename)
main/src/main/java/cgeo/geocaching/downloader/MapDownloaderOpenAndroMaps.java