Whether VS2015 can build project target for Windows Phone 10 and Windows Phone 8.1

Question

Question

Whether Visual Studio 2015 support building targets both for windows phone 8.1 and windows phone 10?

Description

I have a project which needs support both Windows Phone 10 and Windows phone 8.1, I initially created a windows universal project (library) for Windows Phone 10, after finishing my program, I need build for Windows Phone 8.1, but I found the project cannot be built for Windows Phone 8.1 via project Property -> General -> Target Platform as it is disabled.

More details,

I have installed windows sdk10, and sdk8.1.
The project is built with VC++/Windows/Universal/Runtime Component Template

Answer 1

If you need to support Windows 10 and Windows Phone 8.1 as well you can create a project for each and then share code via a PCL or Shared Project. The majority of your code should be able to be shared in order to limit code redundancy. Certainly, there will be some pieces that won't carry over, and these pieces would go in their specific project folders instead of shared.

Answer 2

You probably selected wrong project type in Visual Studio Wizard - Windows Universal Platform introduced in Windows 10 is not backward compatible, so you won't be able to retarget it to Win8.1

In order to support both Windows 8.1 and Win10 Universal you need to create a project for Universal Windows 8.1: With it you will be able to support both Windows 8.1 and Windows 10 Universal