The latest system versions for Amazon’s Kindle Fire HD 8.9-inch Tablet, namely 8.1.4, will improve performance and features on the device, as well as adding the subscribe option for the Kindle FreeTime Unlimited Application.
From what users say, it seems like the touchscreen has been tweaked, auto correction function is fully enabled, and also, the email is now working.
So, if you consider upgrading, firstly check your system version by going to More → Device → About. If the displayed version is 8.1.4, no further action is needed. Otherwise, connect your Kindle device to the computer via USB and copy the downloadable file into the “kindleupdates” folder.
After you ensured that the file transfer is complete, disconnect the device and go to More → Device → About → Update Your Kindle, at which point the tablet will restart and initiate the update process.
When the tablet restarts after the process is complete the update is finished, and if it was successful, the System Version should be 8.1.4.
Now all you need is the downloadable file, that you can get by following the link below. Amazon Kindle Fire HD 8.9" Firmware 8.1.4