The tech behemoth has emailed affected users to inform them that devices released before or during 2012 will no longer receive updates from May 20.
This means that owners of older Kindle models - such as the Kindle Touch and some Kindle Fire tablets - will be unable to download new e-books.
Amazon said it had supported the affected models for years and that active users have been offered discounts to help "transition to newer devices" but some have criticised the company for making around two million devices "obsolete".
One user wrote on social media site X: "I have a Kindle Touch that I've had since 2013, it works great, I bought a book on it a few months ago, and suddenly it's obsolete."
The affected Kindle models are: Kindle 1st Generation (2007), Kindle DX and DX Graphite (2009 and 2010), Kindle Keyboard (2010), Kindle 4 (2011), Kindle Touch (2011), Kindle 5 (2012), and Kindle Paperwhite 1st Generation (2012).
As for Fire Tablets, the models impacted are: Kindle Fire 1st Gen (2011), Kindle Fire 2nd Gen (2012), Kindle Fire HD 7 (2012), Kindle Fire HD 8.9 (2012).
An Amazon spokesperson said in a statement: "Starting May 20, 2026, customers using Kindle and Kindle Fire devices released in 2012 and earlier will no longer be able to purchase, borrow, or download new content via the Kindle Store.
"These models have been supported for at least 14 years - some as long as 18 years - but technology has come a long way in that time, and these devices will no longer be supported moving forward."
Users will still be able to read e-books that they have already downloaded, with their accounts and their Kindle Library remaining accessible on its mobile and desktop apps.
Amazon has also warned that performing a factory reset on the affected Kindles will render them unusable.
Tech industry analyst Paolo Pescatore acknowledges that Amazon's decision may frustrate users but feels that it is "understandable from a security and support perspective".
He told the BBC: "The challenge is that these devices were built for a different era and are not equipped to run newer, more data-hungry services and features."
