The problem is here: "(accepts a 1.0 object but depends on 2.0)"

This case actually has nothing to do with nested dependencies. Your time zone lib is returning a datum with one type, which you're passing to a formatting lib that expects a datum with another type. This can happen if your libs have dependencies that are totally different libraries instead of the same library with different versions. It can also happen if your libs have no dependencies at all. This is not an issue of dependencies but of you not understanding your libs' APIs.