Was just about to suggest that as well. If it is the normal onboard Intel Wireless Bluetooth, more than likely you will not be able to update it to support 4.2 from what I was able to find. You may have to reach directly out to them via their support channel and see if it something that has an update.
Right click on your home button
Select Device Management
Expand Bluetooth
That should show you which you have installed
Double click on it
Click the Driver Tab
Hit Update Driver
Choose "Search automatically for updated driver software"
Allow it to download the most recent version available
Test again (may want to reboot just to make sure)
Worst case you can possibly purchase a Bluetooth 4.2 dongle and try to run it off of that, but I am not 100% on the compatibility with the Flare. That would be something that @AnkerOfficial would be able to help with.
You can also contact Anker support and see if they have a remedy as well. They are awesome and will help you out.
