According to the TechNote, if they're in the date range specified, they need to be replaced. I haven't worked with Point IO much, so I don't know if their firmware can be updated. I think
@jstolaruk's suggestion is for the modules that can be updated (PLC, comm modules, etc.). Personally, I would not upgrade the PLC firmware unless necessary or unless you want to harmonize with other systems in the plant. It may be worth trying as a diagnostic step if you can, though.