Hearts of Iron IV

Thunder at Our Gates launched on June 11 as Hearts of Iron IV’s first Theater Pack, adding country content for Australia, Siam, and the Dutch East Indies (Indonesia). The accompanying free update reworked Division Designer and added Regimental Support, while the DLC introduced Army Headquarters and Ship Captains; Expansion Pass 3 became available on November 12.

• Thunder at Our Gates: Its launch also delivered a new soundtrack and later country-specific additions.

  • Australia: received a new secret path.
  • Siam: received additional late-game content.
  • Dutch East Indies: received additional late-game Indonesia content.

• Expansion Pass 3: Became available, with two further packs announced rather than released.

  • USA, Canada and More: the next Country Pack was announced.
  • Next Theater Pack: a future Theater Pack was announced.

• Energy: Reworked the economy around local Energy.

  • Power Plants: generated electricity based on terrain, including without coal.
  • Dams: generated static Energy and provided state-wide bonuses.
  • Synthetic Refineries and production lines: consumed Energy, while Coal’s effects were later reduced.

• Romania Focus Pack: Was announced and previewed, not released, with its future mechanics and focus paths detailed.

  • Breadbasket of Europe: emphasized agriculture, trade bonuses, population growth, and civilian factories.
  • Balkan Industrialist: offered faster industrial gains while limiting long-term economic potential.
  • International Cooperation: added shared cooperation options; the preview also covered a three-sided civil war and Iron Guard expansion.

• 1.19 balance pass: Continued combat and systems tuning across named versions.

  • 1.19.1: introduced the first feedback-driven balance pass.
  • 1.19.3: incorporated Open Beta changes affecting Tank Chassis reliability, Land Doctrines, Motorized Infantry, Mechanized Infantry, and Self-Propelled Artillery.
  • 1.19.4: delivered a quality-of-life pass focused on reducing clicking and mental overhead.

No Compromise, No Surrender launched on November 20, 2025, expanding the war in Asia with new content for Japan, China and the Philippines. Warships of the Pacific followed on March 17, 2026 with naval models for the Pacific theater.

• Expansion: No Compromise, No Surrender added national content and historical paths for Japan, China and the Philippines, alongside changes to faction management.
• Naval models: Warships of the Pacific added 30 naval 3D models. Paradox announced the cosmetic pack on March 9 before its March 17 release.
• Naval balance: Later updates adjusted submarine visibility and naval supply consumption.
• Developer diaries: Previews discussed the Chinese Soviet Republic, Siam and the Dutch East Indies. The latter countries' expanded content arrived with Thunder at Our Gates in the next anniversary window.

Götterdämmerung released on November 14, 2024, bringing a major Germany-centered expansion with new national focus trees, Special Projects, Experimental Facilities, and military raids. The Graveyard of Empires country pack followed on March 4, 2025, adding four South Asian and Middle Eastern focus-tree overhauls alongside new regional mechanics.

• Götterdämmerung: The paid expansion substantially broadened Germany, Austria, Belgium, Congo, and Hungary.

  • Germany: Added a rebuilt focus tree, Inner Circle, MEFO Bills, Reichskommissariats, and new historical and alternate-history routes.
  • Austria, Belgium, Congo, and Hungary: Added new focus trees, including an Austro-Hungarian joint tree and shared Belgian-Congolese colonial branches.
  • Special Projects: Added scientists, Experimental Facilities, 28 projects, and weapons such as the V1 Flying Bomb, V2 Ballistic Missile, and Project Habakkuk.
  • Military Raids: Introduced targeted strikes against dams, canal locks, resources, experimental facilities, and enemy super weapons.

• Graveyard of Empires: The country pack added new or expanded trees for the British Raj, Iran, Iraq, and Afghanistan.

  • British Raj: Added partition and independence mechanics, princely-state management, railway development, and paths including the Mughal Empire and East India Company.
  • Iran: Added democratic, communist, fascist, and monarchist routes involving Mosaddegh, the Tudeh Party, SUMKA, and the Qajar dynasty.
  • Iraq and Afghanistan: Added their own focus-tree content, new characters, and access to the shared Saadabad Pact branch.

• Prototype Vehicles Pack: Released on May 15 as the final part of Expansion Pass 1, adding new 3D models for historical prototype vehicles.

• AI Force Concentration and Equipment Designer: The AI concentrated stronger divisions for offensives, while the Equipment Designer gained save-and-share support for tank, ship, and aircraft designs.

• Armored Car Battalions and Elephantry: Armored cars received larger formations and artillery-tech bonuses, while tank production costs were rebalanced and Elephantry received revised combat, artillery, manpower, and supply requirements.

Arms Against Tyranny launched on October 10, expanding Hearts of Iron IV’s Nordic theater with new national content for Finland, Norway, Denmark, and Sweden. Trial of Allegiance followed on March 7 alongside the free BOLIVAR update, adding South American campaigns across Brazil, Argentina, Chile, Paraguay, and Uruguay.

• Arms Against Tyranny, Trial of Allegiance, and Stella Polaris: Three substantial releases broadened the campaign’s national flavor.
  • Arms Against Tyranny added Nordic focus trees, Finnish alternate-history routes, and new paths for Norway, Denmark, and Sweden.
  • Trial of Allegiance introduced Brazil’s Integralist, monarchist, democratic, communist, Good Neighbor, and South American domination branches, alongside Argentina’s political and civil-war routes, Chile’s coup-focused tree, and mini-trees for Paraguay and Uruguay.
  • Stella Polaris (1.13.6) delivered another free update with additional content and features.
• International Market and Military Industrial Organisations: The International Market added equipment contracts, buying and selling, subsidies, market access, and AI participation. Military Industrial Organisations (MIOs) gained research and equipment-design integration, initial traits, policies, and a streamlined progression tree.
• Special Forces Doctrine and Joint Focus Trees: Special Forces Doctrine introduced branch specialisms for Marines, Mountaineers, and Paratroopers, including Marine Commandos and new paradrop effects. Joint Focus Trees enabled shared Nordic branches and supported factions such as the Kalmar League, Nordic Council, and Northern People’s Union.
• Major Air Rebalance Pass and Faster Simulation Speed: The Major Air Rebalance Pass reworked aircraft modules, airframes, plane templates, naval combat interactions, torpedoes, and combat widths. Lend Lease Mechanics gained world-tension, ideology, and law restrictions, while Consumer Goods Factories Factor changed consumer-goods calculations. Faster Simulation Speed and Enhanced Multi-Threading Utilization reduced average tick time by roughly 1.5 times.

Hearts of Iron IV: By Blood Alone released on September 27, 2022, delivering Italy, Ethiopia, and Switzerland content alongside the Plane Designer and a rebuilt peace-conference system. Operation Cockpit launched on April 13, 2023, while the May entries for Military Industrial Organisations and International Market previewed future systems rather than confirming their release.

• National focus content: Italy, Ethiopia, and Switzerland received new focus trees and alternate-history routes through By Blood Alone; Ethiopia also gained the War Escalation system, an army overhaul, and a divided regional map.
• Plane Designer and peace conferences: Plane Designer introduced modular Small, Medium, and Large airframes, multi-role aircraft, and Maritime Patrol Planes. Peace Conferences added Take Navy, Resource Rights, War Reparations, Dismantle Military Industry, and Demilitarized Zone demands.
• Career Profile: Awards, Unit Medals, Playthrough Overview, custom achievements, modded-game statistics, and profile customization expanded campaign tracking and replay goals.
• Combat overhaul: War Support gained casualty and strategic-bombing penalties; Piercing vs Armor was reworked, while Logistics Strike, naval hit profiles, and AI Tank Strategy were retuned.
• Operation Cockpit and Nakama: Operation Cockpit launched as a named update, while Nakama Crossplay connected Steam and Microsoft Store multiplayer and replaced PDX MP on the Microsoft Store.
• Military Industrial Organisations and International Market: The May entries previewed Military Industrial Organisations with skill trees, levelling, traits, and task capacity, plus equipment contracts, market access, and CiC payments; these were described as planned systems rather than shipped features.

Hearts of Iron IV: No Step Back released on November 23, 2021, alongside the Barbarossa patch, delivering the game’s largest systems-and-content overhaul in this stretch. The release centered on the Soviet Union while adding the Officer Corps, rail-based logistics, and new tools for shaping campaigns.

• No Step Back content: The expansion and accompanying update substantially broadened military command, Soviet politics, and supply management.
  • Soviet Focus Tree: Added Five Year Plans, an Air Force branch, COMECON, non-Communist routes, Trotsky and Bukharin opposition paths, and civil-war preparation and postwar decisions.
  • Officer Corps: Introduced branch-specific spirits, academy spirits for commanders, preferred tactics, and the ability to promote generals and field marshals into advisory roles.
  • Supply System: Added multiple-hub supply flow, trains and train variants, motorization controls, supply-capital relocation, logistics strikes, and Floating Harbors.
  • Railway Guns: Added researchable support weapons with dedicated movement, capture, damage, and combat-effect rules.
• Habsburg and Holy Roman Empire: Added a substantial alternate-history route.
  • Habsburg Branch: Let players restore the Habsburg dynasty through the Generic focus tree.
  • Holy Roman Empire: Allowed every nation to pursue restoration regardless of its starting position.
  • Royal Marriage Candidates: Added historically grounded candidates and three continuous focuses to the Habsburg route.
• DLC Subscription and Career Profile: The DLC Subscription launched with access to major expansions and cosmetic DLC, while Career Profile began tracking player statistics.
• Air and naval systems: Air Groups simplified management of multiple wings, Intercepting added en-route interception, and the Naval Tech Tree split hull research from naval support; the Ship Designer also barred medium- and light-cruiser guns from the same design.

Battle for the Bosporus released as a new country pack, giving Bulgaria, Greece, and Turkey dedicated focus trees and new political routes. The Eastern Front Music Pack and Eastern Front Planes Pack also launched, while No Step Back was announced as a future expansion rather than shipped content.

• Battle for the Bosporus: The October 2020 release added substantial Balkan and Turkish content.
  • Bulgaria: Added internal factions, military-restriction and rearmament paths, and choices between foreign investment and domestic industrial development.
  • Greece: Added political and industrial paths shaped by debt, instability, and the Hellenic Armed Forces.
  • Turkey: Added non-aligned, fascist, democratic, and communist routes, the Montreux Convention event chain, and Kurdish state management.
• Eastern Front releases: The Eastern Front Music Pack added 13 tracks, while the Eastern Front Planes Pack added 54 aircraft models for Germany, the Soviet Union, Poland, Hungary, Romania, and Yugoslavia. The Immersion Bundle also released with additional cosmetic and audio content.
• Free and base-game additions: The Heavy Cruiser Pack became free for all players, adding cruiser 3D models to the base game, and the Finnish Him! achievement was added for conquering the Soviet Union as Finland without joining a faction.
• No Step Back announcement: The expansion was announced with a Soviet Union and Eastern Front focus, but it did not release in this window. Its previews covered the Tank Designer, Supply Hubs, Railway Guns, a new partisan system, refreshed land warfare and logistics, and upcoming focus-tree work for Poland, Estonia, Latvia, and Lithuania.

La Résistance released on February 25, 2020, adding an Intelligence Agency, recruitable Operatives, espionage Operations, code cracking, Collaboration Governments, and a deeper Spanish Civil War. Allied Armor Pack followed on June 3 with 45 armored vehicles for the USA, UK, France, and Soviet Union, while new focus trees broadened campaigns in Spain, France, and Portugal.

• Espionage: La Résistance added a new intelligence layer.

  • Intelligence Agency: Players constructed agencies, recruited Operatives, upgraded branches, and could become a faction’s Spy Master.
  • Espionage Operations: Infiltration, coups, sabotage, support for resistance movements, and collaboration-building operations became available.
  • Intel Ledger and Code Cracking: Separate Civilian/Industry, Army, Navy, and Air Intel views exposed enemy technology, stockpiles, missions, and temporary decryption advantages.

• National focus trees: La Résistance substantially expanded the political paths of three regions.

  • Expanded Spanish Campaign: Republican and Nationalist Spain received new focuses and a larger Spanish Civil War, including Republican factions, Soviet aid, and anarchist or Carlist developments.
  • Free France and Vichy Regime: France gained distinct focus trees, including a route to restore the old French monarchy.
  • Portugal: Portugal received a new focus tree with Salazar, naval, colonial, industrial, and Spanish Civil War branches.

• World additions: Allied Armor Pack and new nation-forming options added more variety outside the expansion’s core espionage systems.

  • Allied Armor Pack: Added 45 armored vehicles and 32 Colonel Edition tanks, alongside the Allied Speeches Addition with 70 minutes of leader and commander speeches.
  • Al-Andalus and Polynesia: North African countries could form Al-Andalus, while Pacific nations could unite as Polynesia.
  • Iberian and Oceanian Releasables: Catalonia, the Basque Country, Galicia, Hawaii, Tahiti, Samoa, and other new tags became available.

• Systems and warfare: Resistance System Overhaul made occupation more strategically demanding, while Compliance System Enhancements added escalating unlocks culminating in Collaboration Governments. Carrier Mission Penalty Adjustments, the Convoy Stun-Locking Fix, and the Naval Tech Rebalance then reshaped carrier operations, convoy retreats, and ship research costs.

Man the Guns released alongside the free 1.6 Ironclad update, delivering the game's biggest naval expansion through ship design, task forces, naval treaties, and a rebuilt combat system. It also added Fuel, Governments in Exile, alternate American and British political paths, and new Netherlands and Mexico focuses, while the Axis Armor Pack and Hearts of Iron Radio Pack expanded the supporting content.

• Man the Guns naval overhaul: Naval warfare received its largest redesign to date.
  • Ship Design allowed players to research components and refit older vessels, including submarines with snorkels and improved stealth.
  • Task Forces organized fleets around new naval missions and control interfaces.
  • Naval Treaties introduced international rules that countries could follow or defy, while Naval Mines added coastal defense and mine-clearing operations.
  • Naval Zones gained terrain effects, shipping-route controls, and a new spotting phase with distance and ship-role positioning.
• 1.6 Ironclad systems: Fuel became a resource for engines, produced from oil and synthetic refineries, and the update added the Custom Game Rules screen for directing AI nations in single-player and multiplayer. Governments in Exile converted legitimacy into manpower and elite troops, while Amphibious Landing Vehicles strengthened marine assaults.
• Man the Guns national content: The United States gained American Congress routes involving the Old Confederacy and another civil war; the United Kingdom gained early decolonization and monarchy-restoration options. The Netherlands and Mexico also received new national focuses, with the British decolonization route gaining related map and tag changes.
• Naval combat mechanics: The Critical Hits System and Naval Production and Repair Overhaul changed ship damage, construction, and maintenance, while later changes recalculated Naval Supremacy using ship size and effectiveness.
• Axis Armor Pack and Hearts of Iron Radio Pack: The Axis Armor Pack added 53 three-dimensional armor models, including eight German tanks, and Hearts of Iron Radio Pack added faction-specific stations with 35 songs.

Waking the Tiger released on March 8, 2018, making the Chinese Front and alternate German and Japanese histories the biggest playable addition. The free 1.5 Cornflakes update arrived alongside it with new army-command and battlefield systems, while Man the Guns was announced with naval warfare and ship-design plans rather than delivered content.

• Waking the Tiger: The expansion added major alternate-history routes and new national content.

  • Chinese National Focuses: Nationalist and Communist China gained alternate paths emphasizing manpower, diplomacy, and the country’s divided state.
  • Updated German Focus Trees: Germany could pursue new histories, including replacing Hitler or establishing a democratic government.
  • Updated Japanese Focus Trees: Japan gained routes including restoring civilian government or allying with the Soviet Union.

• 1.5 Cornflakes: The free update introduced systems available to all Hearts of Iron IV owners.

  • Chain of Command: Armies could be united under field marshals while benefiting from generals’ skills.
  • Decisions and Missions: Historical decisions and national missions created new uses for Political Power.
  • Acclimatization and Battlefield Equipment Capture: Troops adapted to extreme environments, while armies could capture battlefield equipment.
  • Revitalized Air War System: The air-war model added support for Volunteer air wings.

• Death or Dishonor: The DLC released on June 14, 2017, adding focus trees for Hungary, Romania, Czechoslovakia, and Yugoslavia, plus Equipment Conversion and new Diplomatic and Puppet Interactions for licensing technology and managing subjects.

• Man the Guns: The expansion was announced on May 19, 2018. Its announcement highlighted Enhanced Naval Warfare Mechanics, including detailed warship design and refitting, alongside New Democratic Nation Paths for the United States and other democracies; those features were not confirmed as delivered here.

Together for Victory launched on December 15 as Hearts of Iron IV’s first paid expansion, adding Commonwealth focus trees and the autonomy system. The expansion arrived alongside a series of strategic and performance improvements.

• Together for Victory: The $14.99 expansion added new Commonwealth campaigns and several major strategic systems.
  • Commonwealth Focus Trees: Canada, Australia, New Zealand, South Africa, and India received unique focus trees, leaders, ministers, and alternate-history paths.
  • Autonomy System: Subjects moved through distinct statuses toward independence, with construction, recruitment, and trade affecting autonomy.
  • Lend-Lease and Technology Sharing: Nations could request equipment from allies and share research within eligible groups.
  • Spearhead and Continuous Focuses: New battle-plan orders and ongoing national bonuses expanded strategic planning.
• Warscore System Overhaul, Resource Lack Penalty, and AI Improvements: Warscore began reflecting battlefield results, capitulating nations provided equipment before final surrender, missing resources could impose penalties up to 100%, and naval AI began using strike fleets to support coastal battles.
• Supply optimization: Supply-processing time was cut from 65% of computation to under 6%, contributing to reported 14–18% speed improvements.