Feel free to do so. I still play on 1.7.10 all the time. (Heck. Partially because of this mod, actually.)
And, as far as i'm aware, cauldron isn't being updated anymore. However, there is sponge, so that's nice. It's essentially bukkit/cauldron, but it can be used on single player servers (with forge, as it's designed to work with it) as well.