Wow, I've never had that type curling problem with PLA,
Of course ABS does a lot and HIPS curls some.
Only thing I can think of is that nozzle temp may be too high,
may try lowering it more.
Sounds like the bed temp is about correct.
Maybe you got some ABS that was wrongly labeled PLA ! ;)
'Creator Firmware Version 1.0' is what is displayed on ours also,
Sorry , no ideas how to fix preheat except maybe reload firmware
and personally, as long as it is printing I don't think I would attempt that.