Versions are an integral part of working with models in Master Data Services. Each and every change that occurs to a model is carried out against a given version. So when, for example, you want to add a Member to an Entity, you must pick a version to make the change against. We've brushed over this until now, simply accepting the default version called VERSION_1 that always gets created when you create a model.
The changes that are made to one version (for example, member addition, updates or deletes, hierarchy changes) are not made to the other versions, meaning we can maintain independent copies of master data if we want to. This can help us with a variety of business scenarios, which we will now explore.