Change Mchost24 version?

I just got a Minecraft server from Mchost24 and wanted to ask how can I change the version of my Minecraft server?

At mchost24 your server has a selection field for different versions. Shut down server, choose version, restart server. If you're lucky, the world is safe. If not, then delete the world and have it created again when the server starts.

Been there myself and had no problems. You only have to read yourself, everything is there.