You didn't specify which problem or which thing that broke. However (and based on my previous experiences on that matter), one could face a problem regarding package PGP/GPG signatures upon trying to update. This is because archlinux-keyring is not being updated before the signature checking. That said, a better approach is to always update archlinux-keyring (sudo pacman -S --needed archlinux-keyring) before anything else (sudo pacman -Syu). This way, you guarantee to be up-to-date with developer signatures, needed for pacman to check the validity for every package to be updated/installed. There's also a pacman-key command, but I never had to use that.