I would like to be able to modify the CPUs/Task setting in a srun job submitted in a hold state but in the version of slurm I am running 20.11.7 this is blocked by scontrol

An example where I submit

srun -H -c 2 stress -c 4 -t 10

The job is put in a PENDING state with priority 0 and I will issue a scontrol release once I have changed job parameters. In the above, the job stress -c 4 wants 4 threads, but the user submitted with srun -c 2 and so the job runs with each thread taking 50% of a CPU.

Before the job is released I would like to be able to run a command like below to increase the request

scontrol update jobid 1234567 CPUs/Task=4

but this gives the error

Update of this parameter is not supported: CPUs/Task=4
Request aborted

Is there any way to correct this parameter in a held job before releasing for allocation

The real use cases have complex decision trees to get the correct core count – this could be run before srun but this is a messier and user space solution than capturing the correction algorithms in a Prolog script or similar