Spam keys suck. Wasn't the shop to be removed? Oh, wait, SMF 2.0 isn't out yet. Damn.
Upgrade will automatically correct theme and language files.
Are you talking about upgrade to the current beta or a future one? Because the SMF 1.1.5 to SMF 2.0 Beta 3.1 Public theme converter works very well, even with heavily modified or entirely custom themes.