My Mars is the same, and has been for a while – but honestly I barely notice it normally. I don’t have the LEDs on all the time, so it’s possible it’s taken longer to degrade. On mine, the discolouration on the sides is comfortably within the page margin, so it’s not a concern for me – I don’t notice it when I’m reading, even if I know it’s there and see it quite clearly on a blank screen. I bought the Boyue device in no small part because it’s one of the cheaper Android-based E Ink devices, so good for taking the plunge with, and I expected to be considering a new/better/bigger device if the Boyue was a success in a similar timescale to a mobile phone. So after two years, I’m eyeing up the next generation already, with newer Android support and the Kaleido colour screens.