[ICA-H652v2] After the firmware is upgraded, why can’t I see the picture in the MJPEG video format via web browser?

That’s because the system comes with the newer video format, and the PC needs to install the newer DC Viewer software to decode and display the video on PC properly.
Please go to “Control Panel -> Add or Remove Programs” to remove old DC Viewer software first. Then connect to IP camera via web browser and it will prompt to install the new DC Viewer software in the PC.