So that means you are using TurnKey Linux v13.0. Unfortunately I am not aware OTTOMH what version of Vanilla forums that includes (included). I suggest that you consult the vanilla forums docs to get clarity on the best way to discover that (and perhaps you actually don't even need to...?)

Then you would just follow the upstream instructions for upgrading Vanilla for that version. FYI TurnKey Linux is Debian under the hood (v13.0 = Debian Wheezy) just in case that is relevant. If you are using the Hub then now might be a great time to upgrade to the latest v14.0. TKLBAM is the recommended way to migrate your data across; then do your Vanilla forums update...

A very quick google turned up a doc that may head you in the right direction re upgrading Vanilla: http://vanillaforums.org/discussion/12740/vanilla-2-upgrading-tips But bottom line the best palce to start IMO is creating a backup of your current system and testing it on a new server (to make sure your backup is good). Again TKLBAM is great for that...