Can PMIx support be enabled without rebuilding from source?

We have a compute cluster with 16 compute nodes + 1 head node running Ubuntu 18.04, purchased from and configured by the vendor Microway. The cluster is running SLURM 17.11.2-1build1 as installed from the official Ubuntu package repositories. We are attempting to run software compiled with the OpenMPI compilers version 2.1.1-8, also installed from the official Ubuntu package repositories. However, we are unable to properly execute MPI applications compiled with OpenMPI using the "srun" command from SLURM -- attempting to do so results in N serial executions, rather than a single N-parallel execution. The SLURM documentation indicates that this can be resolved by using PMIx (https://slurm.schedmd.com/mpi_guide.html#open_mpi), however I cannot find any documentation on how to enable PMIx in the version of SLURM that is distributed by the official Ubuntu package repositories.

Can PMIx support be enabled in the official packaged versions of SLURM distributed by Ubuntu, or is it necessary to manually recompile SLURM in order to enable PMIx support?