VXGI there is no option in light source to enable it

Hi! I’ve installed ue4 from github. VXGI version 4.17
At first I got tons of errors when launched GenerateProjectFiles, But reinstalling Visual Studio 2015 with Visual C++ and VS 2017 helped.
Made all those things with Visual Studio, builded it, changed config file e.t.c. But I don’t have option in Light Source to enable VXGI. Also there is no settings in post process volume about vxgi.
Am I doing something wrong?