Amazon is warning users that they need to update old Kindles by tomorrow, or else.
Customers using an outdated software version on Kindle e-readers require an important software update by March 22, 2016 in order to continue to download Kindle books from the Cloud, access the Kindle Store, and use other Kindle services on their device.
This is quite radical, and it’s not clear why this update is so critical. This update is necessary for any device from the original Kindle through the first Paperwhite (which Amazon called the Kindle Paperwhite 5th Generation (2012)).
If you don’t update the device by tomorrow, then you’ll have to manually update it. This means you have to download an update file, and transfer it to the device from a computer via a USB cable. More information about determining which software version you need, and which device you own, is here.