You can upgrade the firmware in one step. But you have to upgrade the cbf project (usersoftware) across all intermediate versions. That means generate a csv file in V8.1, import in V9.x,check. Export a csv in V9.x import in V13... export V13, import V16SP1.
Note regarding the version: V2016 SP1 is not the last stand. It would be better to use the Roll Up RU03 (Several fixed problems included)
Before you generate the csv file in V8.1 you have to do a parameter upload from all parameters, which are necessary for the process (KP, TN, Delay times, limits)