So, is there any way to to monitor or range for any beacon regardless of its ProximityUUID on iOS? The short answer is no.
The long answer involves trying a couple of different ways:
Using the CoreLocation APIs, the obvious way to look for all beacons is to pass a nil value for the ProximityUUID when constructing a CLBeaconRegion. But that doesn’t work. If you try this:
CLBeaconRegion *region = [[CLBeaconRegion alloc] initWithProximityUUID:nil identifier:@"myUniqueIdentifer"];
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