As of now, this feature is only available on the Logos Web App, but will be going through the version 9.9 desktop beta process. We wanted to make our users aware that this feature has been added as well as encourage users to give it a try and provide feedback.
To locate the "Version History" feature, open Sermon Builder on the Web App and make sure the Sermon Info right sidebar appears. There is now a third icon within that area that is shown in the screenshot below...

Once content begins to be created, you will see the timestamps created. Then, in instances where the sermon document is worked on across several different days, you will see the version history broken down by day as seen here. If you click on the small arrow just to the left of the date, it will expand out the different versions captured on that specific day.

Thank you for your help with testing this new addition to Sermon Builder. We hope it's a help to many and absolutely welcome feedback.