It appears this latest version of the package is missing a number of activities. I noticed after I started updating dependencies when all of a sudden my processes wouldn’t validate. Specifically due to the System>File>Delete no longer existing.
Can you aslo share a screenshot of the Project Panel? Where dependencies are listed. I want to check if System activities are installed properly. Also, have you tried using search in the Activities Panel?
Below is a screen shot of the project panel including the XAML code that is complaining about the Delete activitiy. Note that search does not show the Delete and my initial post shows what is unde the System activities.