You need to upgrade from the current version of Cisco Unity Connection to a higher version to use the new features supported with the new version. When you upgrade a server, the new version of Unity Connection is installed in a separate disk partition known as inactive partition. To activate the new version, you need to perform switch version. The following are the two ways to switch to the new version:
Automatic Switching: Allows you to automatically switch to the new version of Unity Connection as part of the upgrade process.
Manual Switching: Allows you to manually switch to the new version of Unity Connection after the successful completion of upgrade.
If you need to revert the server to the previous version, you can rollback to the previous version.