I want get Unreal Engine 4 ,but i dont know about DirectX 10 or lower support…In FAQ everything about DX11, but not 10… So, Unreal Engine 4 supports DX10 or lower?
You should be able to launch with -d3d10 switch to get DX10.
DX9 is WinXP and is being phased out as (not supported) far as I know, but there one can use OpenGL instead.
We support support DX10 / OpenGL 3.3 and above for engine and editor.