1. Connect your NVR to a router with network cable.
2. Use a computer which is also connected to the same router as DVR/NVR
here is software download link
3. Run software Device manager. It will detect many IP address.
If your system is a 4 channels system, there are 5 IPs. One is NVR's IP and other 4 are cameras' IP.
How to judge which one is NVR's IP and which one is camera's IP Below is method.
4. Select one camera's IP and select the upgrading file to upgrade.