Logitech K780 Bluetooth keyboard not working with XA2?

I have a Logitech K780 Bluetooth keyboard. It pairs with my XA2 (Koli, 4.0.1.48), but it does not respond to any keystrokes.
Is there anything else that needs to be adjusted?
What are the technical requirements for a Bluetooth keyboard to work with an XA2?
Is there a compatibility list?