Firmware help from AUS

Hi all, I have a few hikvision cameras which all require firmware update (purchased in 2012 - never been updated). An example of the models is DS-2CD7133-e (mini dome). Does anyone have any advice on how this can be achieved? I have read through the forums and tried a couple of firmware revisions but they fail to update (noted in the 2CD-2xxxx forum thread for firmware). The current firmware is a 2.xx revision.

Is updating possible? I'm in Australia and have looked around but these cameras...

Firmware help from AUS