Hi, I am trying to setting up the OpenMPI software stacks on a GPU cluster, in which the CUDA driver is difficult to upgrade so I have to use CUDA 9.0. However, the released binaries of MOFED are complied with CUDA 9.2. Is it possible for Mellanox to release HPCX in more CUDA versions, or possbly release the source code of HCOLL so I can compile it by myself?

HCOLL is closed source and cannot be released.

Regarding the CUDA, I would expect it to be backward compatible. Is there any failure you are getting when trying to use it?