Normally, upgrading is just a matter of installing the newer version into a separate directory and copying the previous version's
config.inc.php to the new directory. If the previous version is phpMyAdmin 2.6.0 or older, we cannot copy its
config.inc.php to the new version because the file format has changed too much.
An upgrade path or the first-installation path, which should not be taken is to copy
config.inc.php. This is because the default configuration file is version-specific, and is not guaranteed to work for the future versions.
New parameters appear from version to version. They are documented in
Documentation.html and defined in
libraries/config.default.php. If a configuration parameter ...