I’m not sure I get what you mean.
Did you manage to update successfully to 1.7.8?
I guess once you’ve done that, you’ll just need to either change the path that the retro emulators find retroarch, move the retroarch folder to .config, or create symbolic links.
If you have it running, in the online updater option, update assets. And add cores. Then edit the settings as needed. If you want the XMB interface, go into drivers and choose xmb in the menu driver section.
Did that cover what you needed?