If you install config files to the new location and prefer the new config file location over the old, you risk accidental misconfiguration when a system has both config files (e.g. in a build pipeline that installs the software and then copies the config to the old location). It is not impossible to solve, but there are questions that require some care if you have a large userbase and solidified codebase. More care than it takes to do it right the first time.