This update enhances fluidity and performance, improves touch navigation responsiveness, gives you the option to choose which items display on the carousel, and adds the ability to add a password lock on Wi-Fi access.
The update should arrive over wireless and install automatically. If it hasn't arrived by now, you can follow these instructions to manually download and install it. After it is applied, the version will appear as: "Current Version: 6.2.1_user_[some long number]" (Tap the gear wheel (settings) icon > Tap More> Swipe down to get Device and tap it.)
Some of our editors received the update for their Kindle Fires over the Christmas Holiday. Some were surprised to see that the update for their Fire applied without the tablet needing to be connected to its power adapter. It also seemed to automatically apply itself without any kind of announcement, warning or way to opt out or delay it.
The carousel is the large section in the middle of the Kindle Fire home screen. It contains icons for the last several items viewed on the device in a circular queue, with some icons (like Facebook's) fixed and unremovable. The update lets users remove an item by pressing on it for a couple seconds to reveal a menu item "Remove from Carousel". If you view the item again it will show up again in the carousel.
Many users in the comment thread for the update complained that it did not give sufficient control to the carousel, for instance, to keep certain items from re-entering, to fix other items outside of the queue (as with Facebook), or even just to stop the carousel from being updated.
Users on the same thread don't comment as much on the performance fixes, but those that do seem satisfied with them.