Windows Phone 7.5 is a major software update for Windows Phone

Windows Phone

Windows Phone is a mobile operating system developed by Microsoft, and is the successor to its Windows Mobile platform, although incompatible with it. Unlike its predecessor, it is primarily aimed at the consumer market rather than the enterprise market...

, the mobile operating system

Mobile operating system

A mobile operating system, also known as a mobile OS, mobile software platform or a handheld operating system, is the operating system that controls a mobile device or information appliance—similar in principle to an operating system such as Windows, Mac OS X, or Linux distributions that controls a...

 by Microsoft

Microsoft

Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

. Although the OS internally identifies itself as version 7.1, it is marketed as version 7.5 in all published materials intended for end-users. The update was formally announced in New York on May 24, 2011, when Microsoft gave an in-depth preview of the update, shortly before which Steve Ballmer

Steve Ballmer

Steven Anthony "Steve" Ballmer is an American business magnate. He is the chief executive officer of Microsoft, having held that post since January 2000. , his personal wealth is estimated at US$13.9 billion, ranking number 19 on the Forbes 400.-Early life:Ballmer was born in Detroit, Michigan to...

 had disclosed that there would be over 500 features.

Microsoft started rolling out Windows Phone 7.5 to both the United States and International markets on September 27, 2011. The first phones that will come pre-loaded with Windows Phone 7.5 have been slated for release sometime in the fall and/or winter 2011.

Messaging and social integration

• Dynamic Live tile information
• Twitter and LinkedIn integration in the People hub.
• Groups: organize contacts by groups which can also be pinned on the start screen.
• Contact cards now include all the contacts conversation history (SMS, emails, MMS, Messenger, etc.)
• Facebook Places check-in support.
• Windows Live Messenger and Facebook Chat integration.
• Threads: all messaging communication organized in a single thread (Messenger, SMS, MMS).
• Threaded email conversations support.
• Outlook
  Microsoft Outlook
  Microsoft Outlook is a personal information manager from Microsoft, available both as a separate application as well as a part of the Microsoft Office suite...
  
   tasks support.
• Facebook events integrated into the calendar.
• Linked email accounts: multiple email accounts can be combined and linked into one inbox.
• Built-in voice-to-text/text-to-voice functionality, which will allow for hands-free texting or chatting.
• Server search for Exchange.
• Information Rights Management support for emails and Office documents.
• Visual Voicemail

Search/Bing

• Bing Vision: barcode, covers, posters, products scanning, and OCR text translation.
• Bing Audio / Music: Shazam
  Shazam (service)
  Shazam is a commercial mobile phone based music identification service, with its headquarters in London, England. The company was founded in 1999 by Chris Barton , Philip Inghelbrecht, Dhiraj Mukherjee and Avery Wang ....
  
  -like audio recognition.
• Bing Local Scout: "around me" business and POI locator.
• Bing Quick Cards: product/media information, reviews.
• Bing Search: indoor maps (US only), image search results, third-party app integration.
• Bing Maps: turn-by-turn navigation, voice guidance.

Office

• Skydrive and Office 365 documents sync (PDF also supported).
• Excel Mobile now supports adding additional macro functions.
• Microsoft Lync support via downloadable app.
• Added "To-Do" option when editing OneNote pages.

Photo management

• People / Groups gallery with Skydrive and Facebook sync.
• People tagging in the photos with Skydrive and Facebook sync.
• Photo auto-fix - automatically improves sharpness, brightness, etc.
• Pictures tile is now animated.
• Video sharing via MMS, Facebook, Skydrive, and email.
• Twitter integration—Tweet your pics!
• Integration with the People Hub.
• Quick access to the Camera Roll.
• When you choose a photo from within an app, you can now pick from online albums on Facebook or SkyDrive, not just pictures saved on your phone.
• Pin any album to Start, including Facebook albums.

Multimedia

• Zune SmartDJ mix support.
• Artist picture now displays on lock screen when music is played.
• UI change of the media controls on the lock screen.
• Ability to control video aspect ratio during playback.
• Single music track repeat without having to pin it on the start screen.
• Podcast downloads / subscriptions over the air (US only).
• Open / play media content by voice.
• Ability to create and save playlists.

Camera

• UI changes (new icons + added arrow icon on the lower left of the viewfinder to indicate camera roll).
• Settings are now saved when the Camera application is closed.
• Disable/enable shutter sound.
• Support for front facing camera.
• Touch focus and capture—Tap any spot on the screen to focus there and take the shot. (This varies according to hardware—some phones will have tap-to-capture but will still automatically center focus.)
• Review pictures above the lock—Snap a photo when your phone is locked, then take a peek at it above the lock. You’ll only be able to get to photos you just took—better for security.
• Changes for portrait orientation—Now, when you take a picture in portrait orientation, you’ll see it in portrait orientation when you review it.

Games

• Redesigned Games hub with integrated 3D avatar and avatar customization.
• Friends and achievements now integrated in the hub.
• Fast Async for multiplayer games.

Internet Explorer 9 Mobile

• Hardware-accelerated rendering.
• Support for HTML5 audio and video playback.
• Background HTML5 audio playback.
• Geolocation support.
• New JavaScript engine.
• New UI with URL bar at the bottom of the screen.
• URL bar is now available in landscape mode.
• Removal of Find on Page feature
• Moved the "tabs" button to a menu item under the application bar.

Security

• Voice commands are now disabled when the device is locked.
• Complex (alpha-numeric) PIN support.

Other changes

• Internet sharing
• Battery saver: phone automatically disables power consuming services and applications running in the background if the battery is low. Also predicts time remaining on battery.
• Ringtone manager with custom and downloadable ringtones.
• The "People" tile has been reworked and is animated differently than before.
• Search icon and quick jump list added to the application list.
• Support for 16 new languages: Czech, Danish, Hungarian, Dutch (Netherlands), Norwegian, Polish, Portugese (Brazil, Portugal), Finnish, Swedish, Greek, Russian, Korean, Chinese (Traditional, Simplified), Japanese.
• East Asian handwriting recognition.
• Support for new languages and emoticons in on-screen keyboard.
• Hidden WiFi network support.
• Qualcomm MSM7X30 and MSM8X55 support.
• Programs menu will have alphabetical options similar to the people functionality
• Power off now requires a swipe down gesture after holding down the power button for a few seconds.
• Removal of "soft-on" alarm feature
• Modification of alarm sleep interval

Development API changes and additions

• Third-party application multi-tasking and fast application switching.
• Support for background tasks and services/agents.
• Expanded live tiles that can be updated without network connection and can have two sides which flip periodically.
• App Connect: third-party applications can integrate with Bing search, have multiple live tiles, and can have push notifications that link deep ("Deep Toast") into various parts of the application directly.
• Optional 32 bit color support for Silverlight applications with hardware dithering.
• Silverlight 4 support.
• Silverlight + XNA support in the same application screen.
• Raw camera feed access for third-party applications.
• New sensor API combines compass, gyroscope, and accelerometer.
• Improved Listbox control with better scrolling performance.
• Improved WebBrowser control with IE9 rendering engine and system-wide cookies access.
• Clipboard API.
• Hardware-accelerated video decoding in the MediaPlayer control.
• TCP/IP and UDP sockets support.
• Embedded database with LINQ (based on SQL Server Compact 4.0 engine, but without direct SQL execution).
• Background file transfer agent.
• Generational garbage collector.
• NEON/SIMD support for XNA applications....