Well, we’re in the midst of supporting the latest releases of .NET.
For GoXam, the kit for WPF includes DLLs for both .NET Core 3.0 and .NET Framework 4.8, as well as for earlier versions of .NET Framework going back to 4.0.
I think you will find that version 3.0 is very compatible with version 2.2. There have been just a few minor improvements which I didn’t feel comfortable in putting into the 2.2.* releases.
The most interesting thing from the end-user perspective is that there is now a DragSelectingTool.Delay, so that a quick mouse-down-and-drag in the background of a Diagram will start the PanningTool, but a mouse-down-wait-and-then-drag will start the DragSelectingTool. We have found this behavior very handy in GoJS.
Oh, and we are no longer supporting GoXam for Silverlight. R.I.P. Nor WPF v3.5 (VS 2008).