You are very welcome Matthew.
No that is Not what I am saying. You can use your 11.3 remote agents with your 11.3.6 Scheduler.
What I am saying is that the upgrade on the Scheduler node will upgrade the local Agent automatically.
But for the remote Agents you will have to upgrade them separately.
The upgrade of the remote Agents can be done at the same time or later according to your upgrade plans.
In the meanwhile, the old 11.3 Agents DO work with the new 11.3.6 Server.
I hope this can help.
Thanks,
Roya