If the upgrade is to a new version, uninstall and install the newer version Remote Indexer.
Usually there are no changes in a minor version. If there are changes, such as 12.5 to 12.5.2,
take a backup of all jar files from Protect\lib\jar on the Remote Indexer Machine.
Replace all of these jar files from the newer version Enforce server’s \Program Files\Symantec\DataLossPrevention\EnforceServer\<version>\Protect\lib\jar folder.