I'm looking into buying an Android phone, and quite like the specs and looks of the HTC Desire 628. Unfortunately it ships with Lollipop (5.1). Would it be possible for me to upgrade this device to Marshmallow (6) or Nougat (7)? If so, how?
For a phone of this popularity you can only expect something to drop officially, the chance of which is slim (especially in regards to Nougat). Decide what's your priority (aesthetics VS updates) then choose wisely.