The camera firmware can be found at the us.hikvision.com web site.
-Use the search bar on top of the web page and input the camera model number to search for the camera. Then click the picture of the camera to go to the camera's web page. The camera web page will have resources for the camera such as firmware (see picture example below)
A direct URL to the camera firmware page will be https://us.hikvision.com/en/support-resources/firmware/camera (see picture example below).
-Enter the model number of the camera and select the magnifying glass icon to search. The search result will list the camera and then expand the list to see the firmware.