If element version Guid is the same for a certain element in two instances of the saved file then we guarantee that the two elements are identical. One element version covers a period of time that is larger than a single transaction: it is a period between two saves, synchronize to central and reload latest. Thus, in an opened document in-between saves or synchronize actions, this version cannot be used to determine if any particular element has changed. To watch for element changes happening in-session, use event [!:Autodesk::Revit::ApplicationServices::Application::DocumentChanged] .