This page seems to have the most recent software under the download->firmware area. There are other Dahua product pages but they had old firmware. This was the only one with the most recent. This is what my cameras came with when they arrived 12 days ago or so. _V3.120.0000000.21.R.230418
IPC-PDW5849-A180-E2-ASTE
www.dahuasecurity.com
Another tip is I could only get all the camera web page views to work in a browser, with cam video visible, in Windows 11 to work if I used Microsoft Edge but turned on 'Internet Explorer' mode. Chrome, Firefox, Opera all don't work for me in Windows 11, cam video is not visible. MS Edge also does not work unless you do the following for IE Mode.
Go to Microsft Edge, click the '...' elipse top right, Settings->Default Browser> Allow sites to be reloaded in Internet Explorer mode (IE mode) set to Allow.
Then on a web page, click the '...' elipse top right and select 'Reload in internet explorer mode'. Then the camera pages all showed the actual video