In addition to the Bluetooth stack upgrade, the new software brings a new version to load into the USB device.
The current version for any device can be checked running the program Bluetooth Device Information.exe, located in the program files\TDK Systems\Bluetooth Software\BIN folder (if using the default installation).
The firmware version 524 shipped with the 126.96.36.199 stack has scatternet support. This is not present in the version 310 firmware shipped from production. It also has support for the Microsoft Bluetooth drivers for USB.