I don't know whether you use the command line or a GUI to install updates, but the upgrade process did print the following lines (from the install file linked in the other reply) on the screen:
> systemd unit names have been renamed"
> you should systemctl stop and disable cups.service and"
> systemctl daemon-reload, start and enable org.cups.cupsd.service"
This is not meant as a slap on the fingers for not having read this, but more to make you aware that if you are using some sort of GUI to manage Arch updates, you may not get to see the output produced by pacman. If this is the case, you should strongly consider using a different update helper, or simply run pacman from the command line.
If you prefer using a GUI, you should consider kalu as it can also handle AUR upgrades, as well as display news updates from the Arch website which often contain vital information about updates that require manual intervention, such as the recent updates to Java and Intel microcode.
Please note that if you use any other service files that depend on cups.service, you may have to manually update those service files to rename cups.service to org.cups.cupsd.service. This is, for example, the case with the ccpd.service file provided with the Canon CAPT driver in the AUR.