If this update has to do with internet security for the browser, you’ll no longer be able to connect to the internet via Kindle without it. However, you will still be able to download the update to your computer via the Kindle section of the Amazon website and install it manually. Amazon wants you to continue to connect and buy books. Certainly, they would like you to buy a new Kindle, but they don’t want you to be unhappy and go elsewhere.
I’m not at all surprised about the late notification. Kindle support personnel know little about these older devices and were probably late in even creating the update. I think the very existence of the update is a good sign for Kindle Keyboard owners.
https://www.amazon.com/gp/help/custo...deId=200529700
All updates are still there.