Until now, Comcast's Xfinity Mobile service has meant buying one of its locked devices. But what if you already have a phone and want to switch? You now have that choice... if you're firmly in Apple's camp. Xfinity Mobile has enabled an in-store Bring Your Own Device option, but only for "select" unlocked iPhone models. Other manufacturers' phones will have to wait until later in 2018. You can receive a gift card if you trade in a phone that doesn't qualify, although that means settling for a locked handset (and likely getting less than your handset is worth).