Firstly it is useful to know that Wisenet refers to 'firmware' as 'software' (abbreviated to S/W) throughout their site.
How to Update your Wisenet Camera Firmware
It has come to our attention that it is not currently possible to update Wisenet camera firmware when the cameras are directly connected to the NVR.
We have contacted Wisenet and they have said they are working on updates to allow customers to update cameras that are directly connected to an NVR however for the time being the following...
How to Update your Wisenet Camera Firmware