Owners of Kindles made before 2012 must install a “critical software update” by today or they will be disconnected from the internet, Amazon has warned....

Owners of Kindles made before 2012 must install a “critical software update” by today (22nd March) or they will be disconnected from the internet, Amazon has warned.

This means users will no longer be able to sync with the Cloud or access new books from the Kindle store through their device. If the device is not updated by today, users will have to manually update via USB from Amazon's website.

A message on the e-retailer’s website has said: “If you not update your device by 22nd March 2016, you will receive the following message on your device: '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'. If you see this message on your device on or after March 22, you will need to manually install the latest software update for your device."

To install the update before 22nd March, users should go to the Kindle home screen, choose Menu and select "Sync and Check for Items".

The affected Kindles include Kindle 1st Generation (2007), Kindle 2nd Generation (2009), Kindle DX 2nd Generation (2009), Kindle Keyboard 3rd Generation (2010), Kindle 4th Generation (2011), Kindle 5th Generation (2012), Kindle Touch 4th Generation (2011) and Kindle Paperwhite 5th Generation (2012).