"If `proxy.config.james` supersedes the old configuration, I should not have to explicitly specify it in records.config for that to work" Correct. And if the administrator specifies no configuration variable, that's what happens. If the administrator does specify it, then it works. The case of interest is where the administrator does NOT specify the new configuration value and DOES specify the old one. In that case I think it's clear the administrator expects the old setting to work. Your argument is the administrator did that in order to get the default behavior of the new configuration setting?
My experience in actually deploying stuff and working with those who do is this sort of backwards compatibility is highly valued. It makes rolling out new versions much easier. It also seems a common thing to do - look at curl parameters for instance, where old switches are maintained while providing newer equivalent ones. It also doesn't seem different from the discussions about configuration file formats and maintaining the ability to read old formats even after adding the new format.
