From the release:
Dear Boss returns you to the streets of London and the hunt for the enigmatic serial killer known as Jack the Ripper. As the monster continues to prowl Whitechapel, baffling the police and putting residents on edge, Dear Boss gives you new tools to face this terrible threat. Additionally, this new expansion draws you deeper into the historical circumstances surrounding the Ripper killings of 1888 with even more variants than those found in the base game. Alongside the twelve beautifully-sculpted plastic miniatures that replace the Policeman, Jack, and Wretched tokens from the base game, Dear Boss provides the definitive Letters from Whitechapel experience.