Few weeks of rumors and speculations and here we have - new HTC device, called HTC First and created together with (and for!) Facebook. It's surely not a flagship model, but also not a low-end device.
In my article here I was writing about HTC One GSM/LTE (UL) and GSM (U) versions. The question if ROM based on UL firmware can be flashed on U device is still valid, but now we have some more details about these variants.