You could try and download the 5.1 preview dll I compiled from here – I don’t see any reason why it shouldn’t work, even though I just said not to mismatch dlls between versions, but in theory if they haven’t changed anything in that source file between the versions, it should work. Be sure to back up your cureent DLL though!!!
I also compiled a new, 5.2 version of that DLL. They’ve added yet another lock on raytracing, but it really only matters if you have a ray tracing tier 1.1 GPU. Here’s the change I made.