How to upgrade domjudge system from 5.1.3 to 5.3.2 without changing current data

Hi all,

I'm managing a domjudge system ver 5.1.3, and I hold many contests with lots of problemsets and students works there.

Now I installed a new judgehost with domjudge ver 5.3.2, and I coped with this error while connecting judgehost with the legacy domjudge server via APIs, I think that it's an incompatible error. "Configuration variable 'diskspace_error' not found."

I would like to solve this problem, but I don't know how to?

BTW, I also want to upgrade the domjudge server system, but I don't know the procedure must be followed?

Regards