Update: Nevermind. I found it
https://www.amazon.com/gp/help/custo...deId=201504450
I didn't update my DX(G) as I didn't get any email from Amazon with this content:
"If you do not update the devices' software by March 22, 2016, you will no longer be able to access Kindle services or get the update via Wi-Fi or a wireless connection."
Does anyone happen to have the update file? Or just the certificate file that was updated?