+#if wxABI_VERSION > 20601
+ // Helper of Load() and Unload(): returns the URL corresponding to the
+ // given file if it's indeed a file, otherwise returns the original string
+ // unmodified
+ static wxString ConvertFileNameToURL(const wxString& filename);
+
+ // loading resources from archives is impossible without wxFileSystem
+#if wxUSE_FILESYSTEM
+ // Another helper: detect if the filename is a ZIP or XRS file
+ static bool IsArchive(const wxString& filename);
+#endif // wxUSE_FILESYSTEM
+
+#endif // wxABI_VERSION
+