follow the steps :- settings>about phone>software update check if there is any new update or not. if there's a new update thena tap on it and install it. make sure your internet connections is on and you have enough battery and device is cool.
he wants os update...and unfortunately no os update is there for galaxy j7....and the procedure is firmware flash if someone simply update software by mobile data or fluctuating wifi then they will sufferd only with device with many issues
