Wow, thats an old release. To be honest if the box is running fine then leave it alone unless you want to update it. The newest release of Vix is nice and stable on that box as I owned a LX2 for many moons until I ungraded to the new ET8500 and always updated when a new release came out but did notice the box slow over time.
Personally I'd make a backup of your exact setup, flash the new release and see what you think, if your unhappy then flash back you original image :)