Hi @kos_cn
I suspect you do not want to downgrade the firmware.
Probably something else going on?
Are you attempting to connect Hikvision DVR to a Dahua NVR to each other??
Yes, you are right!
Hikvision DVR without HDD, actually I have 3 of them. And I need to record a video in one device (Dahua NVR with HDD) via RTSP.