Are there are keyboards, mice and/or trackpads which will connect at Bluetooth 4 frequency, or are such input devices not made? I installed a Bluetooth 4 USB adapter on my Mini in hopes of mitigating the well known Mini usb/bt/wifi interference problem which is due, as I understand it, to frequency overlap of wifi, bt and usb noise. Taking BT off the card did seem to help, but I realize that everything is still falling back to keyboard and mouse BT, which I assume means that the BT 4 adapter is just operating at the lower frequency. Another possible fix would be to add an 11ac wifi usb adapter and change the frequency of the wifi, which would certainly be doable. I don't want to belabor the issue but being able to understand and reconcile conflicts in techs as ubiquitous as BT and WiFi is a good addition to anyone's practical skill set.