I'm not sure where the industry is at these days, to be honest. So as far as I know all LE devices use the GATT profile (though I wonder about headphones). The LE spec includes HOGP (HID over GATT Profile) which defines a set of services and characteristics for LE HID devices. [1]
Older devices almost certainly use a Classic Bluetooth HID profile, but newer devices like the Apple Magic Keyboard are LE HOGP devices. It uses much less energy so IMO a battery-powered HID device would be pretty nutty to implement using Classic Bluetooth in this day and age.
Interestingly there's no concept of "pairing" in LE devices, just "bonding" (where previously derived keys are persisted and re-used as an optimization). All LE peripherals operate in promiscuous mode by default and vendors have to implement their own pairing system -- or piggyback off bonding.
Older devices almost certainly use a Classic Bluetooth HID profile, but newer devices like the Apple Magic Keyboard are LE HOGP devices. It uses much less energy so IMO a battery-powered HID device would be pretty nutty to implement using Classic Bluetooth in this day and age.
Interestingly there's no concept of "pairing" in LE devices, just "bonding" (where previously derived keys are persisted and re-used as an optimization). All LE peripherals operate in promiscuous mode by default and vendors have to implement their own pairing system -- or piggyback off bonding.
[1] Warning PDF link: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&c...