Amazon has announced a range of new tablets, for the US at least, and with them a new version of its operating system.

Like previous iterations, Fire OS 3.0 (codenamed "Mojito") is based on Android but is heavily layered with Amazon's own portals and applications. It also brings some new features to the party and smooths out the conversion process for developers so that they can offer existing Android apps on Kindle Fire tablets with little or no extra work.

That's why Pocket-lint has decided to give you the full rundown on what the new operating system offers, and which devices it will be available for.

What's new in the user interface?

The existing Kindle Fire operating system offers a user interface that's unlike those found on most other Android tablets. It is effectively locked to Amazon's services and therefore has no access to any of Google's pre-installed apps or integration, such as Google Play. Instead, it presents its own bookstore based on the Kindle library, own media services - such as Amazon Prime Instant Video in the States and Amazon Lovefilm Instant in the UK - and own place to buy and download apps: the Amazon Appstore.

Traditionally, this is all presented in the Carousel - an easy to navigate scrolling format rather than the traditional app or widget desktop aesthetic. Content will appear in a scrollable menu as the main hub, allowing you to instantly find a book, film or app without having to delve into dedicated sections - although that's possible too.

Fire OS 3.0 adds an alternative grid view, allowing you to choose between the recent content available in Carousel mode or a grid featuring favourites.

Cloud Collections adds a way to organise apps, books, newspapers and magazines in the cloud, ready to be pulled down when needed and synchronised across multiple devices.

A 1-tap archive option gives you a reminder if you haven't looked at or used a piece of content for a while. You can then choose to store it in the cloud, thereby saving space on your device, using just one tap.

Kindle FreeTime offers new "For Kids" suggestions to help parents choose appropriate content for their children. And integration for Facebook and Twitter is now baked into the OS, so that sharing to the social networks can be done within the system, not just in apps. Facebook contacts, events and photos integration is now included.

What is the Mayday button?

Available for the Kindle Fire HDX 7-inch and 8.9-inch models specifically, the Mayday button gives you the option to contact an Amazon expert at any time day or night, 365 days of the year. It is built into Quick Settings and once engaged the expert can co-pilot the HDX screen, showing you how to do certain things rather than just trying to explain.

Any other new features?

There are plenty of other additions.

Goodreads is now built-into the reading experience. While reading an eBook, you can check out what your friends are reading, get recommendations, share quotes and write reviews from inside the book software.

X-ray has been improved. As well as giving the same level of information as before, the new TV and film services also list the soundtrack song names as they play on screen - on top of your rented or bought content. Trivia and goofs can also appear, and character backstories are available and will pop-up as the specific actor appears. X-ray has also been expanded to work with music. Lyrics are available and can appear even when offline.

The Fire OS 3.0 also allows you to "fling" content to a TV via a PlayStation 3 (soon to be PS4 too) or a Samsung Smart TV. The tablet will then act as a second screen, giving you X-ray information or even doing something totally different like browsing the web or playing a game. The media content will still play on the TV.

Quiet Time allows you to mute all incoming notifications or calendar reminders at the touch of one button. It can even be linked to come on at the start of an activity, such as reading. And Quick Switch adds a global swipe that will choose between multiple apps with a gesture from anywhere in the system. Unlike normal Android, that can even be between two different books.

A new reading mode gives up to 17 hours of battery life.

Anything else?

Amazon has made things much simpler for developers with Fire OS 3.0. It now has native Android compatibility, so you can expect to see the Amazon Appstore fill much more rapidly. And there is now support for HTML5 apps, so software engineers can adapt their web apps with little fuss.

GameCircle and WhisperSync for Games allow developers to add progress synchronisation across devices and better integration of achievements and the like. Plus, Amazon will give every new customer 500 Amazon Coins (worth around $5) to encourage them to buy apps with the virtual currency. It's essentially aimed at helping developers add in-app purchases to their Kindle Fire games and software.

For enterprise reasons, email has been enhanced, with easier set-up for accounts. And printing of documents now supports wireless printers.

Is it coming for my existing Kindle Fire or Kindle Fire HD?

Amazon currently has no plans to update the software on the existing Kindle Fire or Kindle Fire HD tablets. It states that Fire OS 3.0 will be"available exclusively" on the new Kindle Fire HD and the Kindle Fire HDX 7 and 8.9-inch models.

We're not entirely sure why it won't be available for the original Kindle Fire HD 7 or 8.9-inch devices, considering that the technologies used are uncannily similar to those in the new Kindle Fire HD, but that's what Amazon has said so far.

When will it be available?

The first device to ship with Kindle Fire OS 3.0 will be the new Amazon Kindle Fire HD, which ships in the US on 2 October. It costs $139 (around £86). Pre-orders are open on Amazon.com now.

Read: Amazon announces Kindle Fire HDX tablets and new, cheaper Kindle Fire HD