Idk... I don't want to do it because the last time I updated when there was minor fixes I couldn't connect to multiplayer.. But I will try and see. EDIT: I just logged on with 1.4.7 so I say it is safe to go ahead and update and play.
It's 1.4.7. It's just a bug fix for single player worlds, as when you open your inventory it had a 70% chance of crashing the game - and some other stuff blah blah blah. All mods and servers are backwards compatible - so it's 100% safe to update