There are a few things we've been cooking up in mixbox that may be incompatible with existing, documented code.
An example is the idgen module [1], which was moved to mixbox, but now accepts different arguments (was a dictionary, now a mixbox.namespaces.Namespace object).
We should try to write adapters where possible and limit the impact of moving to mixbox as much as we can.
[1] http://stix.readthedocs.org/en/stable/overview/id_namespaces.html#id-namespaces