Are you looking for the Utf8_XH conversion plugin? This is now called Utf8migrator_XH.
Utf8_XH is a utility library for CMSimple_XH and plugins, offering various tools for working with UTF-8. The developer version is hosted on SourceForge, and contains extensive documentation and a test suite.
It requires a UTF-8 encoded CMSimple_XH installation. It is released under LGPLv3.
Utf8_XH couldn't be tested so far in various environments. It is a so called BETA version. Use with caution!
Installation instructions can be found in the README.