Nokia US has confirmed via support pages that Bluetooth Low Energy (LE) will be coming to all Lumia WP8 devices via the upcoming Black software update. Bluetooth LE was enabled in Lumia 520, 620, 625, and 720 devices via Amber update. This confirmation should put an end to all the questions about support for Bluetooth LE in Lumia high-end devices like Lumia 920, Lumia 1020, etc.
Bluetooth LE allows you to connect your phone with special accessories like heart rate monitors. While doing that, thanks to Bluetooth LE connection, the accessory battery will last much longer, up to months.
It is already available for 520, 620, 625, and 720 with Amber. With Lumia Black software update, Bluetooth LE will be enabled across the full WP8 Lumia range.