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The D01E Kindle is a Kindle Fire 1. You are already running the latest version your Kindle can handle. You don't need to update any further. You will be able to continue using your Kindle services even after March 22.
Refer this article --> http://www.amazon.com/gp/help/customer/display.html?nodeId=200790620
If you have any questions or would like any additional information, please don't hesitate to ask.