Windows Phone versions, Windows and Visual Studio versions

On https://dev.windowsphone.com/en-us/downloadsdk are listed all the Windows Phone SDKs.

 

SDK 7.1

Targets devices with Windows Phone 7.0 and Windows Phone 7.5

Windows® Vista® (x86 and x64) with Service Pack 2 – all editions except Starter Edition

Windows 7 (x86 and x64) – all editions except Starter Edition

Visual Studio 2010 SP1

 

SDK 8.0

Targets devices with Windows Phone 8 and Windows Phone 7.5

Windows 8 64-bit (x64) client versions

Windows Phone 8 Emulator:

Windows 8 Pro edition or greater

Requires a processor that supports Second Level Address Translation (SLAT) http://www.petri.co.il/check-cpu-slat-support.htm

Visual Studio 2012

 

SDK 7.8

Adds two new emulator images to your existing Windows Phone SDK installation. This update supports both the Windows Phone SDK 7.1 and the Windows Phone SDK 8.0. Using this update, you can provide the Windows Phone 8 Start screen experience in your Windows Phone 7.5 apps. You can also test how your apps will run on Windows Phone 7.8 devices.

It’s for both SDK 7.1 or SDK 8 to enable developing for Windows Phone 7.5