Hi I have just ordered the Lumia 640 yesterday and while going over the specs at a comparison site it mentions " Service lights " I did a search on this site but found no mention of this what is it ?
http://www.phonearena.com/phones/compare/Microsoft-Lumia-640,Nokia-Lumia-735/phones/9253,8891
http://www.phonearena.com/phones/compare/Microsoft-Lumia-640,Nokia-Lumia-735/phones/9253,8891