Working when not in front.
WHAT LOCAL NOTIFICATIONS ARE
Scheduled by the application itself, without a server.
WHAT REMOTE NOTIFICATIONS ARE
Sent from your server through Apple's service.
WHAT BOTH REQUIRE
Explicit permission.
WHEN TO REQUEST IT
After demonstrating why they are useful.
WHY
Refusal is difficult to recover.
WHAT NOTIFICATION EXTENSIONS PROVIDE
Modifying content before display, and custom interfaces.
WHAT SILENT NOTIFICATIONS DO
Wake the application to fetch data, without displaying anything.
WHAT TO KNOW ABOUT THEM
Delivery is not guaranteed, and the system throttles them.
WHAT THAT MEANS
Do not depend on them for correctness.
WHAT BACKGROUND MODES EXIST
Audio, location, voice calls, external accessories, background fetch, processing tasks.
WHAT EACH REQUIRES
Declaration, and justification at review.
WHAT REVIEW REJECTS
Background modes declared without a genuine corresponding feature.
WHAT BACKGROUND TASKS PROVIDE
Deferred work the system schedules when convenient.
WHAT TO ACCEPT
You do not control when it runs.
WHAT TO NEVER INCLUDE IN A NOTIFICATION
Sensitive content, which appears on a locked screen.