Apple has been progressively bringing Bluetooth 4.0 connectivity to its mobile devices and personal computers. The mid-2011 MacBook Air (full review here) and Mac mini were the first to get Bluetooth 4.0 and were followed suit by the iPhone 4S, which was the first smartphone ever to get Bluetooth 4.0 connectivity.
All the above are Bluetooth Smart Ready devices, i.e. they can connect to every legacy Bluetooth device out there, like Bluetooth mice and keyboards, and new Bluetooth 4.0 Smart Ready and low power Bluetooth 4.0 Smart devices, like body monitors and watches. Here’s a table below of what can connect with what: