When it comes to implementing Bluetooth support, you can choose between using the open source BlueZ stack or a proprietary Bluetooth stack that can typically be purchased from the Bluetooth controller vendor. One distinction between BlueZ and proprietary Bluetooth stacks is that BlueZ has a core component implemented within the Linux kernel, whereas proprietary stacks typically operate entirely in userspace. Unless the hardware vendor actively supports BlueZ for their customers, another distinction between the vendor's proprietary stack and BlueZ is that certain functionality may be unsupported, despite the community's best efforts to support most Bluetooth hardware.