Configuring Unreal Build System for Windows XP

The Unreal Build System can be configured through the BuildConfiguration.cs to modify the build process to suit a variety of needs. For Windows specific options, you can alter the UEBuildWindows.cs configuration

Adding Windows XP Support

Minimum Spec

Only Windows XP with Service Pack 3 is supported.

You also must have a Video Card which supports OpenGL 3.2.

Building with Windows XP support

WindowsPlatform::SupportWindowsXP

If true, a build of UE4 which is compatible with Windows XP will be created.

To enable XP support, find where it is forced off in the SetupEnvironment and update this, with:

public override void SetUpEnvironment(UEBuildTarget InBuildTarget)
{
    ...

    // Win32 XP is only supported at this time.
    SupportWindowsXP = InBuildTarget.Platform == UnrealTargetPlatform.Win32;

Enabling a Windows XP compatible build forces the compiler to use Windows SDK 7.1. This will mean that any functionality which has been provided by the Windows SDK 8.0 will not compile. You can wrap sdk specific code in a WINVER check:

#if WINVER == 0x0502
    // Windows SDK 7.1 code should live inside this block
#else
    // Windows SDK 8.0 code should live inside this block
#endif

Getting the game running on Windows XP

As Windows XP does not support DirectX 10 or DirectX 11, OpenGL must be included as a target RHI for your game.

You can find the option to include this in the Editor: Edit->Project Settings->Platform->Windows EnableOpenGLForWindows.png

Once you have packaged your game, you should then be able to run the game executable from the binaries directory on a Windows XP machine.