New UpdateScreencastify recently went through an update. If your Google Chrome has not updated the app, you can do so by right-clicking on the Chrome extension, removing it from Chrome, and reinstalling it from the Chrome Web Store. This post is not so much about the use of Screencastify so much, but merely the changes that took place. So if you need a quick overview on those changes, here you go.
If you have never used Screencastify, my old tutorials are available as well. Those are listed below.