However, the base game was also free for the entire week at the time, which makes the new numbers even more impressive. The previous record, 70,997 CCU, was set in September 2022, when Paradox released the By Blood Alone expansion. Shortly after launch, Hearts of Iron IV peaked at 78,108 concurrent users (CCU), according to SteamDB. It added new focused trees for Finland, Norway, Denmark, and Sweden, as well as introduced some bug fixes and changes to in-game balance. On October 10, Paradox Interactive released Arms Against Tyranny, a new paid expansion for Hearts of Ironn IV.