I'm building an access-control feature. My iOS app acts as a BLE peripheral, and a fixed door reader acts as the central. The app produces an encrypted token; the reader receives that token, validates it, and unlocks the door. The reader is a custom, non-iOS BLE device (embedded module), not an Apple device. I need this to keep working while the app is in the background, and ideally after it has been terminated. I've enabled the bluetooth-peripheral background mode (UIBackgroundModes). What I understand so far (please correct me) From the startAdvertising(_:) documentation and prior forum threads, when a CBPeripheralManager advertises while the app is in the background: CBAdvertisementDataLocalNameKey is not advertised, and the advertised service UUIDs are moved to a special "overflow" area that "can be discovered only by an iOS device that is explicitly scanning for them." That seems to imply a non-iOS central cannot discover my peripheral by service UUID once the app is backgrounded. This is exactly my concern. Questions Background discovery — Given the overflow-area behavior, is there any supported way for a non-iOS central to discover an iOS peripheral that is advertising while the app is backgrounded? Or is discovery by a non-Apple scanner fundamentally blocked in that state? Advertisement payload — My token could be delivered two ways: (a) embedded directly in the advertisement (e.g. CBAdvertisementDataManufacturerDataKey / service data), or (b) via a GATT characteristic after connection. In the background, is manufacturer data / service data included in the advertisement at all, or is it dropped like the local name? Characteristic read while backgrounded — If a connection does succeed, can the reader still read or subscribe to a GATT characteristic served by my app while the app is in the background? Any limits on value size or notifications in that state? Terminated state — With State Preservation and Restoration (CBManagerOptionRestoreIdentifierKey + peripheralManager(_:willRestoreState:)), will the system keep advertising and relaunch my app into the background when the reader connects, even after the app was terminated by the system? Does the same overflow-area limitation apply to restored advertising? Force-quit — My understanding is that if the user force-quits the app (swipe up in the App Switcher), the system will not relaunch it or preserve its Bluetooth state. Is that correct, and is there any supported exception? Recommended design — Given the goal (a non-iOS reader must reliably receive an encrypted token from a backgrounded/terminated iOS app), is the peripheral role even the recommended approach? Or should I invert the roles (reader = peripheral, app = central), which seems better suited to background operation? Thanks in advance.