Nokia lumia 520 is the worst phone what I ever seen.it vry bad am facing diffucites on flight mode its stuck it cant go off.the battery is not good to short and delicate.no software update for a long priod a time.no usb connectivity.sometime wifi is ptoblem.i dont like it. Worst ever phone of lumia series. I am facing of probelm in this phones not appreciated.there is a problem of whats app install whan was updated windaw 8.1 flight mode is automatically on and now it is not. Off allways shown flight mode on.so good by nokia lumia 520