The anwer I fear the most
Ok, I just have to grep the "net/minecraftforge/fml/common/registry/IForgeRegistryEntry" strings on files in all the mods to check the bad/old mods (in this instance : Cyclic, journeymap, Magical Map, modnametooltip, Quark, rftools, VillageName : only 7 of 45).