The biggest potential issues are probably with some of the weapons and occasionally suits on magic. Off the top of my head, keep an eye on the Into the Steam weapons and check them against the new corebook, and take a look at suits on spells. For the most part, the new corebook magic pursuits and magia assumes that all Sorcery uses tomes, Necromancy uses crows, etc, and some stuff from the older books (Gremlin bokur, IIRC) need to be tweaked so they work with the update.