
Wibree makes minor changes in the media access control layer of Bluetooth to deliver data rates of up to 1Mbit/second while requiring just 10 to 40 percent of Bluetooth's power consumption. Both Bluetooth and Wibree serve a similar range of around three meters, however Bluetooth can deliver up to 3 Mbits/s.
Later it will follow up with a dual-mode spec that will require minor hardware modifications to the classic Bluetooth spec to support the lower-power Wibree. The changes will require less than a square millimeter of silicon. Not sure if mobile manufacturers will let you retrofit your existing Bluetooth devices by sending it back in. I doubt it.
Source: EE Times