Microsoft have already announced that Bluetooth HID (keyboard) support is finally coming in Windows 10, but it was quietly added in Windows Phone 8.1 GDR2. The problem is this update won’t be circulated to most phones. It is however present on the new Lumia 640 series. 
It’s very easy to setup a Bluetooth Keyboard with your phone once you’ve paired the devices you just type when you’re in an app which accepts text input and it just works. That could be writing an opus in Word or a quick text message. As a developer there is nothing special we have to do to support this. There are a couple of things to be aware of:-
- If the keyboard has special function keys like volume, search, windows etc these do nothing (even if they map to a logical function on the phone).
- The Page Up and Page Down keys raise and lower the soft input panel on screen
- The keyboard won’t allow you to skip to a section in jump lists (like picking a mail recipient for example)
- Although it paired successfully my Symbol CS3070 Barcode Scanner doesn’t actually do anything (When in HID mode it should work as a Bluetooth Keyboard and put the barcode value directly into the keyboard buffer).
There are some interesting subtle visual changes in GDR2. The circular right-arrow button at the bottom of the start screen which provides an alternative to swiping to get to the programs list has been replaced with a more “Big Windows” all apps link
Clear signs of the “oneness” of Windows which will follow!
In The Hand Ltd 