When I look at btmon output of advertising reports for BT Classic for Linux boxes, I see something like this: > HCI Event: Extended Inquiry Result [cut] Device ID: USB Implementer's Forum assigned (0x0002) Vendor: Linux Foundation (0x1d6b) Product: 0x0246 Version: 5.4.0 (0x0540) I am wondering where the 0x540 version comes from / corresponds to about the host software stack version (I couldn't find such a constant in the BlueZ source code or googling around. But for instance a BlueZ 5.64 had this value, so it doesn't match 1:1 to BlueZ). But it seems to change slightly over time for different Linux machines. And I'm also curious about the 0x246 product ID, though it seems like that's always the same for all Linux machines I've seen thus far. Cheers - Jake