It's perfectly safe to upgrade from 02xx - 0253, 03xx - 0368, 04xx - 0479 or 05xx - 0516 because you're staying on the same level of software (train). You only need to be careful if you're planning to go up a software level 02xx - 03xx, then 03xx - 04xx, etc. You don't need to worry about that as you're already at the top software train level. Just follow the link I posted in #998. I followed these the other day when I went from 0245 - 0253 and it was a piece of cake. Rather than starting the engine and leaving it idle, I took it for a drive whilst it updated! Only took 5 mins.
The MU0516 is the version it will go to. When you've done the update and check the version from the update menu, it will show 0516.