Hi,
I saw someone request VNC support for the WP400 some time ago, and I thought it would be useful in one of my own projects as well, so I did some research and managed to get it working using the Debian ARM64 package and libraries. I also created a plugin for WBM to make it easier to manage. WBM-plugin isnt needed tho, can be managed via ssh. Config file for x11vnc placed at /etc/x11vnc/x11vnc.conf
x11vnc-wp400
GitHub: GitHub - somlioy/x11vnc-wp400: x11vnc IPK for WAGO WP400 web panels running firmware 30. · GitHubx11vnc-wp400-wbm
GitHub: GitHub - somlioy/x11vnc-wp400-wbm: Web-Based Management plugin IPK for configuring the x11vnc-wp400 package on WAGO WP400 firmware 30. · GitHub
Tested on WP400 firmware 30.
I have not tested SSL/TLS support in x11vnc. If localhost only is enabled, the server is only reachable locally. Access through an SSH tunnel can then be used, which makes the connection secure through SSH.