Bicentric

Hello! I recently updated my Voltz server from the 1.4 version to the 1.5 version. Upon updating I noticed that most blocks related to the mod that had been place was either removed or changed, all of my pipes and wires were removed, some of my machines were changed to ores, etc... I was just wondering how do I correctly update the server so this doesn't happen? I have a back up of the world available. Thanks, - Bicentric