I'm pretty sure the 8x has bluetooth 4.0 I have an 8x & a Fitbit Flex. The Flex requires bluetooth 4.0 to sync & my Flex syncs just fine on my 8x. Also the Fitbit people have stated on there forums that they have confirmed with HTC that the 8x is an officially compatible Fitbit device, which mean that the 8x must have bluetooth 4.0 in it to work with a Fitbit device. So if the Microsoft Band requires bluetooth 4.0 then the 8x should work just fine.