and much better if you can get backup of all your site and domain and rebiuld your Vps and install kloxo-mr in fresh system
in Kloxo-mr for OS you have a choice between centos5 or centos 6 but C6 have a much more facility for you
kloxo-mr control panel in final version use new best code and configuration for all services and scripts (such az httpd mysql nginx bind php qmail lighttpd,.... )face to old kloxo control panel and if you will have a server without any problem with best performance better fresh install in fresh OS and then restore backup
after install kloxo-mr you can pleasure from use all of best feuture in kloxo-mr nginx - nginx/proxy - lighttpd/proxy - multiple php - many php confguration module .... and all last update version of basic services