Archlinux mainline just announced the EOL for i686 in archlinux:
Following 9 months of deprecation period, support for the i686 architecture effectively ends today. By the end of November, i686 packages will be removed from our mirrors and later from the packages archive.
For users unable to upgrade their hardware to x86_64, an alternative is a community maintained fork named Arch Linux 32. See their website for details on migrating existing installations.
Transition from the Official Repositories
If you plan to move from the official repositories to our community maintained repositories, follow these steps:
Put any mirror from our mirrolist into /etc/pacman.d/mirrorlist.
Execute pacman -Syy archlinux32-keyring-transition to install our keyring transition package signed by one of the x86_64 archlinux devs.
Run pacman -Syuu for a full transition.
Note, that some packages are currently newer in the official repositories and will be downgraded, therefore.
Also note, that packages found in your package cache won't match the signatures from archlinux32 - either allow pacman to delete these cached packages or run pacman -Sc to clean your cache before you start and after you finish upgrading.
See https://archlinux32.org/download/ for more information, including installation media.