If you own a pre-2013 Amazon Kindle you'll need to update it before Wednesday this week, or you may be stopped from downloading purchased books or buying new ones.
Kindle models that are older than 2013 need the new software update for a critical fix. If you don't do it by March 23, Amazon will take away its online services such as the book store.
It also means you'll lose access to Amazon's cloud library where your purchased books and documents sit.
If your Kindle is affected, Amazon will have already sent an email to you to explain the situation.
As soon as possible
Those who don't update by March 23 will be greeted with an error message when they attempt to connect to the internet, but it's assumed you'll still be able to read installed books from your device.
If you don't update over-the-air by the cut-off date you'll have to connect up your device to a computer to update via a USB connection.
We wouldn't recommend leaving it that long as you'll need to download the latest firmware files, move them to the Kindle and select 'Update Your Kindle' on the device.
Amazon said in a statement to techradar, "Periodically we ask customers who have not updated their device software in a while to update their devices to ensure that they are operating with the latest software, and that their device remains compliant with continuously evolving industry web standards.
"Customers will be unable to use Kindle services after March 22, 2016 unless this update is complete so we want to encourage customers to complete this update so that their device experience is not interrupted."