Configuration Manager creates a new revision of an application when new changes to the application or its deployment types ...

Configuration Manager creates a new revision of an application when new changes to the application or its deployment types are submitted. 

Restoring a revision brings the current application back to a previously known state by creating a new revision based on a selected revision. Duplicating a prior revision will create a new application based on the selected revision. 

Revisions cannot be deleted unless there are no other objects referring to that revision.