eZ Platforms stores versions of all content. This is has been available for a in eZ Studio since version 2016.04 and as of 1.4 in eZ Studio. Users in studio can view content versions and preview them on the layout.
As a user I would also expect to be able to restore old versions to use via the Studio interface, but currently this can't be done.
Steps to reproduce:
1. Clean eZ Studio install
2. Create an article
3. Set title to "My Article (Version 1)" and save
4. Navigate to studio to view article in site view
5. Edit article, set title to "My Article (Version 2) and save
6. New version is published
7. Use versions widgets to view old version
8. Click edit
9. Latest version is opened in editing - title: My Article (Version 2)
In addition the version widget implies that you could edit old versions (see attached image).
See video for example: https://youtu.be/4OgTmR-_ZWA