To make use of the full functionality of Send for Review from X-Author Contracts described in this guide, you must send only documents that belong to Version Aware agreement records and have the X-Author Contracts for Outlook add-in installed. For documents that are non-Version Aware, tracking and managing of reviews will be disabled. Likewise, review tracking is not enabled if the Outlook add-in is not in use (emails can still be sent and X-Author Contracts functionality is still available for users with access).
For more information on making agreement records Version Aware, see Contract Document Versioning.