Currently the helper script script.skinshorcuts doesn’t work under the super early versions of Kodi 18, this means if you upgrade to it, you will lose all menus on the Metropolis home screen.
You will not be able to undo this easily. (Well unless you know how to move the “skin.metropolis” folder out of the addons folder via a samba share and restart Kodi.)
There is an extremely covoluted way to get any pre-made menus to work again under Kodi 18 sort of, but it is involved and still won’t let you modify any of them.
All skins that use it are going to have to wait until the developer of that helper script changes some things around. You can read more about it here.
Metropolis is not supported under Kodi 18 yet anyway. This is just a heads up. (I know some of the users like to switch to the cutting edge really early so I just wanted to warn them.)
TLDR: If you use Metropolis (or any other skin with dynamic home menus) don’t upgrade to Kodi 18 yet.