What do you mean by local bluetooth address? On Android Device.id field will be a MAC address of a device and on iOS it will be autogenerated UUID. However this value on iOS is not guaranteed to be persistent.
@Cierpliwy any ideas how to fix non-persistent UUID?
You could put your device's unique ID in advertisement data under manufacturer data (0xFF) if you want to detect your device without connecting. Another option is to advertise you device's specific service UUID (0x07).
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What do you mean by local bluetooth address? On Android
Device.idfield will be a MAC address of a device and on iOS it will be autogenerated UUID. However this value on iOS is not guaranteed to be persistent.