Hi,
Anyway, I'm also looking to upgrade the software 568.2MM
Firmware should be available from your local dealer or failing that I suggest you contact one of the HH friendly dealers that post on here.
I'll PM you their contact details, I'm sure someone will be able to help you.
... can I then update firmware from 2.0 directly to 2.5b9, or what is recommended?
You can install either version of the software, it is not dependent on what has previoulsly been loaded.
The important thing is once the firmware has been installed, to re_TYPE the unit to set the base level configuration ... and then of course configure from their to suit your requirements.
Regards,
Carl