If you missed the Kindle update deadline, don't worry. There are a few things you can do to get your device updated.
First, try restarting your Kindle. This will sometimes trigger the update process. If that doesn't work, connect your Kindle to your computer and download the update manually from Amazon's website.
If you're still having trouble, contact Amazon customer service for kindle help. They should be able to walk you through the process and get your Kindle updated in no time.
And, also you can visit how to update kindle for a step-by-step guide for updating the kindle.