[DiapDealer]

I had some issues with this update (Fire HD10) where the simplified categories weren't appearing and old books/magazines kept appearing on the Home screen. Attempts to hide them resulted in a notification that Kindle was "Managing your content" being stuck. It couldn't be dismissed without restarting the device. Which resulted in the previously hidden books/magazines being placed on the Home screen again. Lather, rinse, repeat.

Long story short: I had to tap to download the books/magazines in question to the device and then long-press and choose "Remove from device" to get them to disappear without prompting the stuck notification. Once all problematic titles were downloaded/deleted, the simplified categories presented themselves and everything began working as it was intended.

I post this case others encounter the eternal "Managing your content" notification and/or titles that refuse to stay hidden on the Home screen.