The adaptor is pretty readily available from different sources. The fact that New Potato hasn't bothered to update the device to work directly with the Lightning connector, which Apple introduced 3 1/2 years ago, gave me pause. New Potato's TuneLink Home seems like an alternative, though. It functions as a stationary, omni-directional IR code transmitter that your iPhone/iPod directs via Bluetooth. No more expensive than the FLPR plus a Lightning adaptor. (It also turns your mobile device into a music player for your home stereo, if that's of any interest.)
Right now, since I play most of my music via my computer and Audirvana Plus, I'm leaving my Bel Canto turned up to my usual maximum desired volume and controlling volume through the A+ remote app. Works, but still would like an actual remote control.