Unfortunately the way this was addressed does not fix the problem. See this commit for an updated riak_test that shows how it fails in a mixed cluster when going from a new node to an old node.  Ideally, vclocks through PB should be encoded exactly the same way in a mixed cluster than they were in the old cluster, even though that makes things more complicated because PB was encoding in a different way to the HTTP interface, which messes with the refactoring to clean it up.