Subversion has a number of configuration files which are consulted by clients and servers of all version pedigrees. The runtime configuration files (~/.subversion et al), svnserve config files, and so on. As we add new options to these files, we should be noting which Subversion versions will honor those options. It is not unreasonable to think that my runtime configuration area could have been created by a Subversion 1.7 client, but that from time to time I need to use a 1.6 client on the same machine. Users in such situations might be confused as to why, when they modify a new-in-1.7 config option (in the file, or via the --config-option switch), it seems to have no effect on their 1.6 client's behavior.