I would imagine, not a thing. Frankly, you might not even notice. It's possible that some of the NPCs in those adventures will have strategies laid out based on spells that have changed (namely, haste), but that's easily ignored. (Haste is still arguably an OK spell for them to cast in 3.5.)
You might find that some monsters are a bit different (namely fiends), or an NPC monk's attack bonuses might not jive with what the 3.5 rulebooks say, but really, who cares? It will still all work.
You might just doublecheck encounters ahead of time (again, particularly with fiends) just to make sure that in an encounter that the module says is CR 16, and it's now CR 20 (such as with a pit fiend, for example, although I don't think either module uses pit fiends).
Have fun!