The upgrade is available for all Oracle Exalytics customers who are currently on Oracle Exalytics Release 2.1 (Base Image 2.0.0.1.el6).
If you are currently on Oracle Exalytics Release 2.1 (Base Image 2.0.0.1.el6) and want to upgrade to Oracle Exalytics Release 2.2 (Base Image 2.0.0.2.el6), then backup the current system running Oracle Exalytics Release 2.1 (Base Image 2.0.0.1.el6), complete the full ISO installation of Oracle Exalytics Release 2.2 (Base Image 2.0.0.2.el6), and restore the backup.