text: We recommend that you upgrade the FSA Agent on the Windows computers on which it is installed. Support is provided for backward compatibility, but new features may not be available until the FSA Agent version is aligned with the Enterprise Vault server version.
  Do not install the FSA Agent on Enterprise Vault servers. Enterprise Vault servers do not require the FSA Agent.
  As part of the upgrade process, you are prompted for a compulsory restart of the file server.
  Enterprise Vault 12.3 does not support File Blocking. If you are upgrading from Enterprise Vault 12.1 or earlier, the upgrade process removes the Enterprise Vault File Blocking service from the file server.
  FSA Agent installation requires an up-to-date root certificate on the target computer. Certificate updates usually happen automatically over the Internet. If the certificate is out-of-date, for example because the computer has no Internet connection, the FSA Agent installation fails with a "Signature verification failed" error in the FSA Agent installation log. For more details and for instructions on how to update the root certificate, see the following technical note on the Veritas Support website:
  https://www.veritas.com/docs/100023437
  You can upgrade the FSA Agent from an Enterprise Vault Administration Console, or by installing the files manually on the file server.
  To install or upgrade the FSA Agent you must use an account that is a member of the local Administrators group on the file server.
  If you upgrade the FSA Agent from the Administration Console then if the file server's firewall is enabled it must be suitably configured. Otherwise the Administration Console wizard fails with the message "Error: The RPC server is unavailable". See the following technical note on the Veritas Support website: