This article is exclusively about the Windows Phone OS version history and the list of features available on it.

List of Windows Phone Versions

This table describes the list of Windows Phone OS versions and their release number.

Windows-Phone-Versions.jpg

List of Windows Phone SDK and their support for Windows Phone App Development:

Windows-Phone-skd.jpg

Note: You can use the Windows Phone 7.1 App feature in Windows Phone 8.0 App, whereas you cannot use the Windows Phone 8.0 App feature in Windows Phone 7.1 App.

Features that are available/not available:

  1. You can upgrade the application that targets Windows Phone OS 7.1 to OS 8.0.
  2. You cannot add a reference that targets Windows Phone 8 in a Windows Phone 7 project.

OK. How to target my app in Windows Phone 7 and Windows Phone 8?

There are a few shortcut ways to make your app to run in both WP7 and WP8.

1. Create a Windows Phone OS 7.1 app that runs in both Windows Phone 7.1 and Windows Phone 8

In order to do this, ensure that you should not use any of the Windows Phone 8 controls or features that make your app fail to run in a Windows Phone OS 8 targeted device. Do use the common controls and features that are applicable to both OS (7.1 and 8).

2. Create Windows Phone 7.1 project and Windows Phone 8 project individually

In order to do this, create the WP7.1 and WP8 projects separately. The cons of this is that you must update both projects for changes. Hence, this is not professionally recommended.

3. To use "Upgrade to Windows Phone 8.0" option

Features available in Windows Phone OS 7.1 and Windows Phone OS 8.0:

The following are the most important features that are available in the Windows Phone.

Windows Phone OS 7.1 Features Windows Phone OS 8.0 Features

CDMA Support, Deeper FacebookIntegration

All features in Windows Phone OS 7.1

Messaging and social integration

Support for WXGA (1280×720, 1280×768) resolutions, 1080p screen resolution support

Search/Bing

Support for MicroSD cards, IE10

SkyDrive, Microsoft Lync, To-Do, Office 365

Simplified porting of Windows Store apps to Windows Phone 8

Video Sharing via MMS, Facebook, SkyDrive and email

Nokia map technology

Integration to People Hub and Twitter

Native 128-bit Bitlocker encryption, Secure Boot

Pin any album to Start

In-app purchases

Deeper Multimedia Support

Possibility to take screenshots

Camera Enhancement

Kids corner, Rooms, Live Apps

Multiplayer Games Support

Google accounts. Windows Phone 8 now supports the CardDAV and CalDAV protocols that allow people to sync Google contacts and calendar information when they get new phones

IE9, Increased Security

Global Screen Rotation lock menu item.

Support for 16 new languages

New Driving Mode feature to ignore calls and texts

Hidden WiFi network support

Access Point menu item to set-up MMSand Internet Sharing

East Asian handwriting recognition

Internet sharing

Third-party application multi-taskingand fast application switching

Silverlight + XNA support in the sameapplication screen

New sensor API combines compass, gyroscope and accelerometer

LTE support

Location awareness icon

For more features related information please refer to http://en.wikipedia.org/wiki/Windows_Phone_version_history