I'm developing a custom keyboard, and I would like certain data to sync across the user's devices. In the containing app, that's straightforward, and I already have my keyboard and containing app sharing data. But if the user makes a change on a device while the custom keyboard is displayed on another device, I don't see any straightforward way of letting that custom keyboard know, so it can update its display accordingly.
I think I can have the container app get updated, and then possibly inform the custom keyboard via the filesystem, but this is exceedingly clunky.
Since CloudKit subscriptions require responding to push notifications, I'm not sure there's a better way, is there?