Amazon just released the newest version of their Kindle Fire OS. This one is for the Kindle Fire HD and the HDX. Here's the full changelog below:

Kindle Fire OS 3.1 changelog:

  • Find and share books with Goodreads: Goodreads on Kindle lets you connect with the Goodreads community to follow friends and see what they are reading, and share and rate books on your Kindle Fire.
  • Organize your content with Cloud Collections: Organize your content library into collections like "Favorite Books" and "Sports Apps" that are synchronized with compatible Kindle devices and reading apps.
  • Watch movies and TV shows on another device with Second Screen: Fling movies and TV shows from your Kindle Fire to your 2013 Samsung Smart TV or PlayStation 3 using Second Screen.
  • Learn more about books with Smart Lookup: With the Smart Lookup feature, you can quickly look up words in the dictionary or Wikipedia or translate text in a book.
  • Print from Your Kindle Fire: Print Word, Excel, and PowerPoint documents, photos, e-mails, calendar events, and contact information from your Kindle Fire to a printer that supports mobile printing.
  • Free up storage space with 1-Tap Archive: With 1-Tap Archive, your Kindle Fire groups all content that has not been used recently so you can move it to the Cloud with just one tap.
  • Enhanced enterprise features: Manage security certificates and connect to your company’s Wi-Fi network—whether you’re at home or at work—with remote VPN capabilities.
  • Set alarms and view additional time zones with the Clock app: Use the all-new Clock app to check the date and time, set an alarm clock, and more.