Upgrading 2.2 to 2.6

I'm still a newbie although I've been running since October last year. It's great that I've not had to do a lot once I got the initial config issues worked out (except one big outage, that's I worked out on my own), but now I'd like to consider an upgrade to 2.6. I looked around but don't see anything documentation or messages here discussing migration. My search query was "2.2 2.6 upgrade migrate". I have no idea what I need to do to migrate my data and configuration off. Do I just copy the config files and my DNS setup. What about voicemail messages? What else do I have to take into consideration?

Here's a really newbie question. I saw a post where someone cut and pasted the output of a command that showed the version of *, OS, etc. was this cut and pasted together or is there a command that dumps the current versions of all the components of trixbox, including the trixbox version. If not what I know how to get the OS ver, but what about *, FreePBX, etc?

Thanks,
David