I am trying to find out about the availability of BLE scanning for advertisements when a watchOS app (on watchOS 26.4 with CoreBluetooth) which starts running a HKWorkoutSession becomes dimmed, ie. due to the user lowering their arm. From my understanding there is still availability for ongoing scanning whilst in the dimmed mode. If this is correct, what settings are required (e.g. using background capability for 'Workout Processing', 'bluetooth-central', etc), and does scanning whilst in background mode limit to requiring service uuids in scanForPeripherals? Also if scanning is throttled, is there an 'estimated' inter scan time? Thanks
Availability for BLE background scanning on watchOS whilst dimmed
Bluetooth scanning in the background on watchOS is not only throttled, but works in a whole different manner than on iOS, and has its own additional limitations.
You might want to take a look at the sample Interacting with Bluetooth peripherals during background app refresh and also refer to the WWDC Session Get timely alerts from Bluetooth devices on watchOS to understand who BLE background scanning works on watchOS.