The was the free patch released alongside the Battle for the Bosporus country pack for Hearts of Iron IV . While the main expansion adds paid focus trees for Turkey, Greece, and Bulgaria, the free update provides significant refinements to existing Balkan content and general gameplay. Key Free Features of Update 1.10 ("Collie")

If you own specific older DLCs, the 1.10 update also provided "free" bonus content for those expansions:

: Received a reworked focus tree for Yugoslavia and tweaks to Romania's starting position.

The "Collie" patch focused on improving accessibility and expanding the game's map without requiring a purchase:

For those looking for the full experience, including the deep-dive historical and alternate-history paths for Turkey, Greece, and Bulgaria, you can find more details on the Official Paradox Interactive Page .

: Added a special infantry model with a Pickelhaube for Unaligned Germany.

: The Heavy Cruiser 3D Asset Pack , which was previously exclusive to the Colonel Edition of the game, was merged into the base game for all players.