pacman -Syu barfs error: XYZ: signature is unknown trust

Things kept getting better and better. Following the recent pacman upgrade, I was now facing issues with regards to package signatures. I had already successfully completed the keyring initialisation and I was a bit stumbled as to what exactly I was doing wrong.

You remember all those /etc/config saved as /etc/config.new messages. Yes, as it turns out these are important. Given you haven’t modified your pacman configuration (perhaps added to the HoldPkg list recently?), you can safely accept the new values:

$ [sudo] mv /etc/pacman.conf /etc/pacman.conf.pacprev
$ [sudo] mv /etc/pacman.conf.pacnew /etc/pacman.conf

Re-run [sudo] pacman -Syu and you are on your way.