More up to date FW can be found here most of the time for cameras:
https://www.mydlink.com/download
Scroll to the right to select your camera model.
Thanks, the link you provided only has the latest 1.14.02 firmware. Previous versions are not offered. The only reason I have a 1.13 is because I kept a copy back when it was the latest. It would appear that 1.13 is nowhere on the Internet.
As an act of desperation, I tried re-doing everything with the DCS-5029L camera using a Windows 10 machine, (I normally use Mac). This resulted in the exact same problem. The camera would only work locally, and refused to access mydlink.