Data Exchange Framework is the foundation for Dynamics CRM Connect.It provides the ability to define the synchronization processes and data mappings that allow data from Dynamics CRM to be exposed in Sitecore, and data from Sitecore to be exposed in Dynamics CRM.
If you are upgrading from a previous version of Dynamics CRM Connect and you have tenants configured, this tool provides the ability to upgrade those tenants. See the Dynamics CRM Connect installation guide for more information.