In order for screens to appear in the screen history, you'll need to follow this process when replacing old screens with new screens.
To view your screen history:
1. Go to your prototype homepage.
2. Click on the appropriate screen.
3. Click the clock icon at the bottom of your screen to go into History Mode.
4. View the left column of the screen to see a list of versions. Click a version to view it.
Note that you cannot restore old versions of screens from History Mode.