Replication Agent uses the RAX-15_5 directory name.
If you have an existing Replication Agent 15.5 or 15.6 installation and want to keep this version separate, install Replication Agent 15.7.1 SP100 into a different directory. Replication Agent 15.7.1 SP100 installer does not overwrite any previous version of Replication Agent installed in the existing RAX-15_5 directory.