Amazon has been working on enhancements to the user interface (UI) for its Kindle devices. Giving things a slightly new look and feel with further updates coming later in the year. The update appears to be targeting models from over the last 6 years or so, covering everything from menu layouts to the drop-down settings menu.
As additional changes roll out later in the year, you will also see changes to the library and home screens. This would be one of the first times in a number of years now that Amazon has decided to touch the visual interface.
In order to make sure you grab the update, make sure you are connected to Wi-Fi and plug the Kindle into its power source. It will eventually check for updates on its own, or you can try triggering the update process manually via the settings menu. You can check the list of current firmware versions for each model via the page here to see if your Kindle is currently using the most recent.
Kindle still remains the victor as the best e-reader solution on the market. This is probably why Amazon has never felt the need to change anything. However, there seem to be some creative juices flowing somewhere. It will be interesting to see what the company has planned for the library and home screen. Hopefully, it will be easier to find things when you have an extensive library of books installed.
