There has been released several enhanced render drivers for UT. They're both for D3D8, OpenGL and contain many new settings and a few new features.
Downloads
Enhanced OpenGL Render Driver v3.4 (111kb) -> Updates
(Link changed by Shade)
Direct3D 8 Render Driver v1.2 (41 kb) -> Updates
(Link changed by Shade)
Note: These are only Render Drivers and not Engine Core Renders. They enhanced the support for Direct3D and OpenGL covering several new settings.