A new version is created each time someone saves their changes to the cloud. When you view all versions of a Revit model, you can select a previous version to restore if needed.
If another user restores a Revit model while you are accessing it, you are notified that your model is no longer compatible with the model stored in the cloud. You can discard your changes and open the latest version of the cloud model, or you can save your changes in a new model. The new model cannot save changes to the cloud again with the restored version of the cloud model.
To view versions of a model
Manage Models panel
(Manage Cloud Models).
(Actions), and click View Versions.
To search, enter text in the search box to locate one or more versions. Click the Version, By, or Time column headings to sort the list of versions shown.
To restore a version of a model
(Restore).
The version you selected is now the latest version.
(Refresh).