The Bluegiga WT-32 is 2.1 + EDR. For audio applications this is the latest technology.
Bluetooth v4.0 is the latest incarnation of bluetooth technology, overall. It includes a "Low Energy" mode of operation that allows for the transmission of small packets of data with ultra low energy consumption. This low energy mode is not meant to be used for audio applications, it is extremely low bandwidth. It is meant to be used on wireless sensors, like - temperature, humidity, heart rate, weight scales, etc.
The confusion comes from the fact that some Bluetooth devices supporting the BT v4.0 Core Specification are "dual-mode", meaning they support both Bluetooth "Low Energy" and Bluetooth "Classic". A good example is an iPhone, which has an internal "dual-mode" BT system. With your iPhone you can connect to a Headset over "Classic" BT to answer a call or to listen to music. But you can also for example, connect to a Heart Rate Monitor via BT Low Energy. These dual-mode devices are also known as Bluetooth Smart Ready.
Elroy does not need to be "dual-mode", it only requires the Bluetooth "Classic" functionality. Thus, Bluetooth 2.1+EDR is the current technology for this application.