The plugins have been updated for 5.1 on Github:
WebUI - 5.1 - 5.0 - 4.27
JsonLibrary - 5.1 - 5.0 - 4.27
HttpLibrary - 5.1 - 5.0 - 4.27
They include new UE5 documentation with updated installation instructions to use the Marketplace directory instead of the Messaging and Runtime directories.
If you are experiencing a black screen then you most likely enabled DirectX 12 for Nanite. You will need to go into your widget blueprint and disable accelerated paint on the WebUI widget if you plan on keeping DX12 as your default renderer. This is mentioned under “known issues” on the releases page.
Also I have an update for shared textures in the RHI helper (accelerated paint) and got it working for DirectX 12, but I haven’t had the time to finish it yet. I was hoping 5.1 would have already included DX12 support for accelerated paint so I wouldn’t have to finish it. But as usual, we probably just need to update it ourselves.