Microsoft today announced and previewed Windows Phone 7.1 (codenamed Mango), which the company says will include over 500 new features. Frankly, with everything that is in the update, we're surprised it's not called Windows Phone 8.

The Mango release will be available for free to Windows Phone 7 customers and is scheduled to ship on new phones beginning this fall. Details on device update timing will be provided closer to availability.

Microsoft has a lot slated for Windows Phone. In terms of communications, the company wants to make it easier to connect and share with the following five main features:

  • Threads - Switch between text, Facebook chat, and Windows Live Messenger within the same conversation.
  • Groups - Group contacts into personalized Live Tiles to see the latest status updates right from the Start Screen and quickly send a text, email, or IM to the whole group.
  • Deeper social network integration - Twitter and LinkedIn feeds are now integrated into contact cards, and Mango includes built-in Facebook check-ins and new face detection software that makes it easier to quickly tag photos and post to the Web.
  • Linked inbox - See multiple email accounts in one linked inbox. Conversations are organized to make it easy to stay on top of the latest mail.
  • Hands-free messaging - Built-in voice-to-text and text-to-voice support enables hands-free texting or chatting.

Microsoft wants to integrate apps directly into the core experiences of the phone. In addition to making it easy to get timely notifications and updates from apps right from the Start Screen, the Mango release will also surface apps as part of search results and within Windows Phone Hubs. Here are the three main app improvements that are coming:

  • App Connect - By connecting apps to search results and deepening their integration with Windows Phone Hubs, including Music and Video and Pictures, Mango allows apps to be surfaced when and where they make sense.
  • Improved Live Tiles - Get real-time information from apps without having to open them. Live Tiles can be more dynamic and hold more information.
  • Multitasking - Quickly switch between apps in use and allow apps to run in the background, helping to preserve battery life and performance.

As for the browser, IE9 is coming. The Mango release will connect the Web to the unique capabilities of Windows Phones, such as location awareness, camera, and access to apps. Here are four online enhancements to look forward to:

  • Internet Explorer 9 - A browser based on the powerful Internet Explorer 9 and including support for HTML5 and full hardware acceleration.
  • Local Scout - Provides hyperlocal search results and recommends nearby restaurants, shopping, and activities in an easy-to-use guide.
  • Bing on Windows Phone - More ways to search the Web, including Bing Vision, Music Search and Voice so it's easy to discover and decide.
  • Quick Cards - When searching for a product, movie, event or place, see a quick summary of relevant information, including related apps.

On top of all this, Microsoft has announced new OEM partners: Acer, Fujitsu, and ZTE. Of course, Nokia is also on board, as are the existing manufacturers Samsung, HTC, and LG. Curiously, Dell, which currently makes the Venue Pro, was not mentioned anywhere.

Microsoft also took the opportunity to declare that there are now more than 17,000 apps available on Windows Phone Marketplace. Access to apps will be expanded by launching Windows Phone Marketplace in new countries.

Support for additional languages is also being added. Microsoft has confirmed it will support the following additional languages: Brazilian Portuguese, Simplified and Traditional Chinese, Czech, Danish, Dutch, Finnish, Greek, Hungarian, Japanese, Korean, Norwegian, Polish, Portuguese, Russian, and Swedish.

Last but not least, a beta release of the free Windows Phone Developer tools, which will be used to create the next generation of Mango apps and games, should be posted as a public download to Microsoft's website by tomorrow. It's odd that Microsoft doesn't have it ready yet, but it's possible the company wants to draw out the hype around this update.

"Seven months ago we started our mission to make smartphones smarter and easier for people to do more," Andy Lees, president of the Mobile Communications Business at Microsoft, said in a statement. "With 'Mango,' Windows Phone takes a major step forward in redefining how people communicate and use apps and the Internet, giving you better results with less effort."