Monday mornings aren’t that bad actually, I’ve found the issue 
Here some description:
- Mapping plugin (the one I develop now) installed in Revit with reference to Objects.dll 2.5.2 in Appdata folder
- Updated Speckle to 2.6 so the Objects.dll is updated to 2.6
- Did not update the installed Mapping plugin
Solution
- Found out that Revit Speckle is also not able to launch
- Deleted the installed Mapping plugin
- I’ll update the references later and install it again, will confirm it here if the issue is solved
Speckle Revit now works again, and running my updated code through the addin manager also gives the expected results, the objects are now available in the right type.
As you can see from this issue we are very dependend on the updates of Speckle. If our plugin is finished, we probably have to constantly update it paralelly to the updates of Speckle which is a bit annoying. I’m not sure if there are is any clever solutions for that one (I also have limited C# and Revit plugin knowledge, I mostly develop full stack with Python / Vue), that would really help. I have been thinking about incorporating it in the Speckle manager before, would be really nice if that’s possible, but then this will still be an issue.