Hello Codeforces!
I just got a mail from my leader this morning, which says that the IOI 2013 syllabus will be used at IOI 2015.
It's explained in this note in misof's syllabus page.
So, explicitly excluded topics in the IOI 2013 syllabus won't be needed, essentially:
max flow and bipartite matching algorithms
implementation of any general balanced tree (e.g., AVL, treaps, splay trees)
Hope it helps!
Since it's IOI 2013 syllabus, it just means that the intended solutions won't use them. There might be conceptually easier solutions using them, that's why I think learning those algorithms would be a better idea.