According to Amazon: To update your Kindle, ensure you are connected to a Wi-Fi network and that your battery is fully charged. Tap the Quick Settings icon in the upper right corner of your device, then tap "Sync." The software update will automatically download in the background and will be applied once download is complete and the device is asleep.
You can even download the update directly from Amazon and sideload it. It's a big update, 181 MB.
http://www.amazon.com/gp/help/custom...deId=200790620