Push notifications to trigger background sync

[SimonPickup]

I don't know if this is at all feasible given the various background limitations Apple has, but one though for the iOS to iOS case might be to use a push notification to attempt to wake the app on the other device. (This might need to be opt in, depending on the privacy implications of sending the push notification.)

Originally posted by @rkjnsn in #7 (comment)

[SimonPickup]

I had been thinking about this too. Hopefully it could also be triggered from non-iOS devices if using custom discovery or relay servers. My understanding is that background activity triggered from a push notification is limited to 30 seconds so that would limit the usefulness.

[TCB13]

@sjpickup what about iOS Shortcuts? Maybe something can be done with running from time to time without showing the app?