When upgrading Remote Indexer to 15.8 MP2, modified configurations will be overwritten with a new indexer.properties configuration file.
Release : 15.8 MP2
Component : Remote Indexer
Typically, in most cases an update to a MP will not overwrite this configuration file. However, in this instance upgrading to version 15.8 MP2 performs a full uninstall/reinstall due to some changes. This only effects remote indexer upgrading to 15.8 MP2, and not Enforce or Detection servers.
Backup configuration files and make note of all changes. Once upgrade is complete, restore the file or re-add the changes.