Some Kindles could stop working soon. Flickr/Neeta Lind Amazon is warning owners of some models of the Kindle e-reader that their devices could stop working properly if they don't download a new update by Tuesday, The Verge reports.

Kindles should automatically download and install the update if they're turned on and connected to Wi-Fi. But if they're not, then the devices won't be able to connect to the internet and download new books.

Amazon has posted a notice online about the update and has also emailed affected users.

Those who don't manage to update your Kindle by Tuesday will see a message on screen that reads: "Your Kindle is unable to connect at this time. Please make sure you are within wireless range and try again. If the problem persists, please restart your Kindle from the Menu in Settings and try again."

The only way to fix a Kindle that didn't receive the update is to connect it to a computer and manually install the update.

Here, via The Verge, is the list of Kindle devices affected: