Luanti has not been updated for a while from 1.15.1 to the most recent 1.16.1, several updates have already passed and a warning message appears that it is not the most recent version for a while.
The Arch package is at that version too.
Cachy is just re-packaging the Arch one with optimizations.
https://archlinux.org/packages/?q=luanti
It seems to have been flagged as out of date .. but we likely wont be getting a luanti upgrade before they do.