errore: impossibile eseguire l'operazione richiesta (impossibile soddisfare le dipendenze)
:: package-query: richiede pacman<3.6
:: pacman-color: richiede pacman<3.6
:: pyalpm: richiede pacman<3.6
pacman -Sy --needed pacman-color pyalpm package-query
choose "n" when archlinux asks for upgrade the packages.
Then, Arch will try to upgrade other packets (and pacman-4 is among them).
At the end of the process, you will have pacman 4.
At this point, probably you experience another problem: the packages now are signed and not recognized by archlinux because you've not the public keys of developers.
If this is your situation, you can fix this problem following this doc:
Or this (in italian)
If you have problem, knock.