I set my render options to use XPU. In the past it was working well with materials such as the Principle Shader. Now I tried to build a full MTLX tree and it doesn't work. My render options are setup for XPU with filters but the Houdini does a CPU render.
What's happening?

There was a brief bug where XPU was not working.
But I think it is now fixed.
Can you now get a basic XPU scene working with the latest build? (eg torus without any material)

I tested this a bit further. I think Karma XPU render is working. I have a laptop with an Nvidia graphic card and it's working fine. I also have a desktop with an Intel GPU and there, I thought it was not working but in fact, it did work, but very slowly. I'm afraid my Desktop rig is a bit too slow and old...