The ArcGIS Data Store relational data store has been a required component of a base ArcGIS Enterprise deployment since 10.6. Beginning with ArcGIS Enterprise 11, you cannot upgrade directly from 10.6.1 or earlier releases. Therefore, if you need information about replacing a managed database with a relational data store, see the documentation for the intermediate version to which you will upgrade prior to upgrading to ArcGIS Enterprise 11.0.