What model Kindle do you have? It may have already done the software update automatically if you have the WiFi turned on. Current Kindle software version history here: http://www.amazon.com/gp/help/customer/display.html/ref=hp_bc_nav?ie=UTF8&nodeId=200529680
General information:
https://en.wikipedia.org/wiki/Amazon_Kindle
It’s an old Touch. I only use it on long flights, so it is rarely turned on. My usual device is the Fire.