Any sufficiently advanced bug is indistinguishable from a feature.
This chapter briefly points out some changes in the requirements and domain analysis. The noteworthy modeling and UML tips of interest are related to the NextGen SSDs and the Monopoly domain model.
No refinement is needed for the use cases this iteration.
However, at a process level I recommend (as does the UP) a second short one- or two-day requirements workshop this iteration (near the end ...