Hearts of Iron IV Patch 1.19.3 Brings New Country Content and a Broad Balance Pass

Hearts of Iron IV Patch 1.19.3 closes out the game’s post-release work for Thunder at our Gates with new country content and a wide balance pass. Australia, Siam, Indonesia, and New Zealand all receive new options, while several changes from the Open Beta Summer Edition move into the main game. Paradox also delayed Hearts of Iron IV’s next major expansion and placed a separate quality-of-life update ahead of the next Expansion Pass, as detailed in the September roadmap.

Paradox described the update as the final patch aimed specifically at Thunder at our Gates in its Patch 1.19.3 announcement on Steam. The balance work covers headquarters, facilities, artillery, support companies, doctrines, armored equipment, and naval bonuses.

Among the player-facing additions are the Pan-Thai Empire formable, Indonesia’s Nusantara and Maphilindo decisions, Australia’s New Guard path, a sixth research slot for Communist Australia, new Midway events, and Australasia for New Zealand. The patch also improves supply handling, adds HQ-related UI information, adjusts AI behavior, and fixes multiplayer and out-of-sync problems.

Patch Notes for Hearts of Iron IV 1.19.3

This update’s biggest mechanical changes affect support units and doctrine rewards. Regimental Tank Destroyers and Self-Propelled Anti-Air units now have higher equipment requirements and lower defensive and offensive modifiers, while line artillery receives several stat increases. The patch also adds new content for the countries introduced with Thunder at our Gates.

Balance

• Add a tracking of total participation in a combat to award HQ capture to the most participating country.
• Halved supply usage for light/medium/heavy armored HQ’s.
• Added supply usage to motorized army HQ battalions.
• SIA: Removed Production Efficiency Cap from Agrarian Economical Policy.
• SIA: Removed Research Speed and Factory Output from The Army of Siam.
• AST: Stretch the Fleet, Battle of the Ocean, Workers Educational Association and Equal Pay reduced to 35 days.
• AST: Red Fred Paterson gained +0.20 Daily Political power for his Voice of Workers trait.
• AST: Communists can now also prospect the 2nd and 3rd Iron Mines (Iron Monarch and Iron Prince)
• AST: Infiltrate Trade Unions in X reduced from 75pp to 50pp.
• AST: Instigate Revolution reduced from 150pp to 100pp.
• SIA: Slightly nerfed long war bonus, buffed intermediate war.
• SIA: Reduced Recruitable Population Factor from 15% to 10% from ‘Agrarian Economical Policy’.
• Land, Air and Naval Facility Base Facility Cost reduced from 12000 to 10000. Additionally, its scaling Cost increased from 5000 to 6000
• Land, Air, Naval and Nuclear Facility construction is now affected by the Infrastructure.
• Infantry Guns no longer get benefits from Infantry Support Weapons research, and instead get their benefits from Artillery tech tree improvements.
• Infantry Guns and Rocket Battery scaling effect with technologies has been reduced. (+5% Soft Attack for the Infantry Guns per Artillery Technology, +10% Soft Attack for Rocket Batteries from Rocket Artillery technologies, and +5% Soft Attack from the Improved Guidance). Infantry Guns no longer receive Defense boost from the Technologies.
• Removed the +10% Piercing and +10% Hard Attack on motorised from the 1940 Anti-Tank Technology.
• Anti-Tank Upgrade Technology (1939 Anti-Tank Artillery Technology) bonus to Piercing to the Tank Destroyers changed to +5%
• Self-Propelled Anti-Air Regimental Support Units and Tank Destroyer Regimental Support Units technology benefits are reduced compared to their line counter-parts. This includes Bofors Swedish Technology.
• Engineer III – Flame Tank bonus to attack in the Urban Terrain reduced from +10% to +5%
• Engineer IV – Flame Tank bonus to attack in the Urban Terrain reduced from +10% to +5%
• Engineer IV – Assault Engineers bonus to attack in the Urban Terrain reduced from +15% to +10%
• Helicopter Logistics Company Supply Reductions from Technology have been increased to -15% per technology.
• Artillery Equipment I has been adjusted to provide the following stats: Soft Attack +1 (from 25 to 26), Defense +1 (from 10 to 11), Breakthrough +4 (6 to 10)
• Artillery Equipment II has been adjusted to provide the following stats: Breakthrough +6 (from 7 to 13), Hard Attack +1 (from 2 to 3), Piercing +2 (from 5 to 7)
• Artillery Equipment III stats has adjusted to provide following stats: Breakthrough +8 (from 8 to 16), Defense +1 (from 18 to 19), Hard Attack +2 (from 2 to 4), Piercing +4 (from 5 to 9)
• Rocket Artillery Equipment I has been adjusted to provide the following stats: Defense +1 (from 12 to 13), Breakthrough +8 (from 9 to 17), Soft Attack +2 (from 30 to 32)
• Rocket Artillery Equipment II has been adjusted to provide the following stats: Defense +1 (from 15 to 16), Breakthrough +8 (from 12 to 20), Soft Attack +2 (from 38 to 40)
• Motorized Rocket Artillery Equipment has been adjusted to the provide following stats: Defense +1 (from 15 to 16), Breakthrough +8 (from 12 to 20)
• Breakthrough Penalty on the Heavy Howitzer, Rocket Launcher and Improved Rocket Launcher reduced from -4 to -2.
• Armored Car Equipment IC Cost reduced from 3.5 / 5.5 / 7.5 / 8.5 to 3 / 4.5 / 6 / 7.5
• Support Artillery now has -50% to Soft Attack, Hard Attack, Defense and Breakthrough from previous -40%
• Support Rocket Artillery now has -50% to Soft Attack, Hard Attack, Defense and Breakthrough from previous -40%
• Support Anti-Air equipment requirement Increased from 20 to 24.
• Motorized Anti-Air now belongs to the Anti-Air Unit Category.
• Heavy Weapons Company and Motorized Heavy Weapons Company Organization has been increased from 20 to 30.
• Heavy Weapons Company and Motorized Heavy Weapons Company Max Strength has been increased from 0.4 to 0.6
• Infantry Guns and Rocket Battery Equipment needed was increased from 4 to 6.
• Infantry Guns and Rocket Battery stat adjustments have been normalized and are now -75% to Defense, Breakthrough, Soft and Hard Attack. (Previously it was (-80%, -60%, -70%, -60%).
• Anti-Air Battery Equipment needed was increased from 12 to 16 and Manpower needed from 120 to 180.
• Anti-Air Battery Breakthrough, Soft Attack and Hard Attack penalties were lowered from -80% to -60%.
• Anti-Tank Battery Manpower needed was increased from 120 to 180.
• Soft Attack penalty from Anti-Tank battery has been lowered from -80% to -60%
• Light, Medium, Heavy and Modern Tank Destroyer Regimental Support units are for now excluded from the ‘Tank Destroyer’ category. They still benefit from the Tank Destroyer Regimental Support category.
• Light, Medium, Heavy and Modern Tank Destroyer Regimental Support units now require 15 Tank Destroyers instead of the previous 10. For now I will refer to them as TD-RS (Tank Destroyer Regimental Support)
• Light, Medium, Heavy and Modern Self-Propelled Anti-Air Regimental Support units are for now excluded from the ‘Self-Propelled Anti-Air Artillery’ category. They still benefit from Self-Propelled Anti-Air Regimental Support category
• Light, Medium, Heavy and Modern Self-Propelled Anti-Air Regimental Support units now require 15 Self-Propelled Anti-Air instead of the previous 10. For now I will refer to them as SPAA-RS (Self-Propelled Anti Air Regimental Support)
• TD-RS and SPAA-RS: Fuel Consumption for them has been increased from 33% of the equipment to 40% of the equipment
• TD-RS and SPAA-RS: Armor Value reduced from -33% to -66%
• TD-RS and SPAA-RS: Defense lowered from -25% to -50%
• TD-RS and SPAA-RS: Soft-Attack lowered from -33% to -66%
• SPAA-RS: Air Attack reduced from -15% to -25% and Hard Attack from -33% to -66%
• TD-RS: Hard Attack reduced from -33% to -50%
• Added Essential (Equipment) Blocks for the following units: Heavy Weapons Company and Motorized Heavy Weapons Company, Light Flame Tank, Medium Flame Tank, Heavy Flame Tank, Headquarters Staff, Engineer Staff, Reconnaissance Staff, Military Police Staff, Maintenance Planning Staff, Hospital Group Staff, Logistics & Service Staff, Signal & Intelligence Staff, Naval Liaison Staff, Forward Air Controller, Special Operations Coordination.
• Adjusted Essential (Equipment) Blocks for the following units: Helicopter Med-Evac, Helicopter Transports.
• Helicopter Brigade and Helicopter Logistics now will have proper Fuel Consumption instead of having -100%
• Helicopter Logistics Company base Supply Reduction has been increased to -15%
• Military Police Training Time reduced from 180 to 120
• Motorized Military Police Training Time reduced from 200 to 120
• Mobile Infantry 1 Reward: Cavalry Recon now receives bonus +10% to Defence and Breakthrough.
• Mobile Infantry 3 Reward: Lowered Soft Attack Bonus to Infantry Guns and Rocket Batteries from +15% to +10%, now also increases Defense and Breakthrough by +5%
• Mobile Infantry 5 Reward: Motorized Heavy Weapons Company gets +10 Organization from +5.
• Defensive Postures 1 Reward: Heavy Weapons Company now also receives +0.2 Entrenchment
• Defensive Postures 4 Reward: Soft Attack bonus to Infantry Guns and Rocket Batteries reduced to 10%
• Assault Infantry Adoption Bonus: Bonus to Support Artillery attack has been increased from +10% to +20%
• Assault Infantry 1 Reward: Bonus to Infantry Guns was removed.
• Assault Infantry 2 Reward: Bonus to Anti-Tank Battery and Anti-Air Battery reduced from +10% to +5% (Hard Attack, Piercing, Air Attack)
• Mounted Infantry 4 Reward: +0.05 HP to Mounted Infantry unit category was replaced with the battalion adjusters to the Cavalry Recon to give +5 flat HP to the Mounted Infantry
• Mounted Infantry 4 Reward: Reduced the Speed Bonus to Cavalry Recon and Cavalry to +40% (for a total of 8 kph instead of the previous 8.4 kph)
• Mounted Infantry 5 Reward: Increased Speed Bonus to Artillery, Anti-Air, Anti-Tank and Rocket Artillery to +100% (for a total of 8 kph)
• People’s Militia 2 Reward: Infantry Guns Soft Attack bonus reduced from 15% to 10%. Infantry Guns now get +10% Breakthrough
• People’s Militia 3 Reward: Now requires 50 Mastery like the other rewards in this doctrine.
• Great War Infantry 3 Reward: Support Artillery now provides +10% Bonus to Breakthrough to Leg Infantry from previous +5%
• Great War Infantry 3 Reward: Infantry Guns and Rocket Battery now provides +10% Soft Attack bonus instead of +20%
• Great War Infantry 5 Reward: Now also provides +5 Max Entrenchment
• Fire Concentration Adoption Bonus: +5% Defense bonus to Line Artillery changed to +10% Breakthrough bonus
• Fire Concentration 1 Reward: +5% Defense bonus to Line Artillery changed to +10% Breakthrough bonus
• Fire Concentration 3 Reward: +10% Breakthrough Bonus to Line Artillery and Support Artillery changed to +10% Defense Bonus and +5% Soft Attack Bonus increased to +10%. Bonus to Infantry Guns and Rocket Batteries was removed.
• Fire Concentration 5 Reward: Bonus to Artillery and Rocket Artillery removed. Infantry Guns and Rocket Batteries now get +10% Defense and +10% Breakthrough
• Anti-Tank Frontline 1 Reward: Bonus to Anti-Tank Battery brought in-line with Line Anti-Tank. Anti-Tank Support now also receives the same bonus.
• Flying Batteries 1 Reward: Motorized Heavy Weapons Company bonus (+10% Soft Attack, +10 Organisation) was removed.
• Flying Batteries 3 Reward: Armored Signal Company now provides +0.2 Strength (from 0.8 to 1) to Line Artillery.
• Air Cavalry 2 Reward: 0.03 HP bonus is now being replaced with Maintenance Company Battalion Adjuster to the Helicopter Support Companies, giving +0.5 HP to each
• Mobile Recon and Support 5 Reward: Breakthrough bonus to TD-RS and SPAA-RS changed to +5% Hard Attack and +5% Air Attack respectively
• Self-Propelled Support Adoption Bonus: Soft Attack bonus reduced to +5%, Air-Attack bonus reduced to +5%
• Self-Propelled Support Reward 2: Soft Attack bonus provided by Recon units reduced to +5%
• Self-Propelled Support Reward 3: Speed Bonus reduced to +10% from +30%
• Self-Propelled Support Reward 4: TD-RS and SPAA-RS now get +5% Hard Attack and +5% Air Attack respectively, and +5 Organization
• Siege Artillery 2 Reward: Plains Movement bonus to Super Heavy Artillery and Self-Propelled Super Heavy Artillery replaced with 0.1 Recovery Rate
• Siege Artillery 4 Reward: Urban Bonus Attack reduced from +20% to +10%, and added Urban Defence Bonus of +10%. Soft Attack bonus to Infantry Guns & Rocket Battery reduced from +10% to +5%
• Armored Spearhead 3 Reward: SPAA-RS Organization bonus reduced from +10 to +5
• Armored Infantry Support 2 Reward: Piercing Bonus removed for TD-Regimental Support.
• Armored Infantry Support 5 Reward: Air Attack reduced from 10% to +5% and removed the +5 Organization bonus.
• Mobile Defense 3 Reward: +5% Air Attack for SPAA-Regimental Support was removed.
• Mobile Defense 4 Reward: TD-RS Organization bonus increased to +10, other benefits to TD-RS removed
• Tank Destroyer Force 5 Reward: TD-RS +10% Hard attack and Piercing was removed.
• Mission Type Tactics Adoption Bonus: Daily Command Power gain has been increased from +0.02 to +0.2
• Infiltration Tactics Adoption Bonus increased from +5% Planning Bonus to +10% Planning Bonus
• Infiltration Tactics 3 Reward, Daily Command Power Bonus increased from +0.01 to +0.1.
• Desperate Defense can ALSO be adopted if a country has at least 10% Surrender Progress AND at least 50% War Support. In other words additional options to adopt this Subdoctrine have been added. Further tweaks to this adoption requirements will likely happen in the future
• Flying Batteries 1 Reward: Now also gives +5% Soft Attack and +10% Breakthrough to the Units previously affected by this milestone
• Flying Batteries 5 Reward: Now also gives +5% Soft Attack and +10% Defense to the Units previously affected by this milestone
• Anti-Aircraft Cruiser Adoption Bonus: Reduced Naval AA bonus from +20% to +10%. Added +10% Armor Bonus to Heavy Cruisers
• Anti-Aircraft Cruiser 4 Reward: Bonus to Destroyer Anti-Air reduced from +20% to 10% and Light Attack from +20% to +5%.
• Patrol Boats 2 Reward: Bonus to Torpedo Attack reduced from +20% to +10%.
• Torpedo Primacy 1 Reward: Bonus to Torpedo Attack reduced from +20% to +10%.
• Torpedo Primacy 3 Reward: Bonus to Depth Charges for Destroyers reduced from +20% to +10%.
• Torpedo Primacy 4 Reward: Bonus to Sub Detection to Destroyers reduced from +20% to 15%.
• Torpedo Primacy 5 Reward: Bonus to Sub Detection to Heavy Cruisers reduced from +20% to 10%.
• Hunter Killer Groups 1 Reward: Bonus to Sub Detection increased from +15% to 20%.
• Hunter Killer Groups 3 Reward: Bonus to Depth Charges increased from +10% to 20%.
• Light Task Forces 3 Reward: Bonus to Destroyers for Light Attack and Light Piercing reduced from +20% to +5%.

Gameplay

• AST: Focus Pleading Britain & Inevitably Independent now available with national unity government even despite incorrect leader.
• AST: Added flavor event Battle of Brisbane (AST_political_events.10).
• AST: Added event to change flag for independent Democratic Australia.
• SIA: Added Elephantry tech on game startup.
• Elephantry is now a support company instead of a normal battalion, giving attack and logistic bonuses to artillery and certain terrain.
• Added armored cars HQ’s if you have unlocked “La Resistance”.
• Added events for Japan and the USA that can trigger after a naval battle at Midway.
• AST: Added a 6th Research Slot to the Communist path as a mutually exclusive option vs merging factions with the Comintern.
• SIA: Added the Pan-Thai empire formable as an extension of the Greater Thai Empire.
• Added decisions to Indonesia to form Nusantara and Maphilindo.
• Indonesian decision to unify Nusantara no longer requires control over Pedang and Singapore. Added follow up decisions to integrate Singapore & Pedang if Indonesia occupies them
• SIA: Asian Democratic Compact now gives a flat 0.1 daily pp gain
• AST: Added a New Guard path.
• AST: Now starts with 1933 aircraft technologies.
• NZL: Australasia now available to NZL.
• Made ‘Maphilindia’ easier to achieve by only making you control the Indian states instead of also owning them.
• Battalion Adjusters now scale with the Equipment and Manpower status of the Sub-Unit. E.g. Super Heavy Artillery with Siege Artillery Sub-Doctrine no longer gives Army wide Soft-Attack Bonus due to the sheer force of will and imagination.

Stability & Performance

• Improved performance to evaluate country from scope traversal in ScopedVariables (this, prev, from and root).
• Fix OOS that could occur when playing in different languages
• Fixed a bug where on reloading a save the supply system could slowdown massively. (Thanks Ender156 for your detailed report)

UI

• Enemy HQ map counter item now requires intel before saying someone is deployed there
• Withdrawing HQ map counter item’s clock tooltip now says when the withdrawal is blocked
• Various confirm pop-ups now say that the HQ will not be able to complete its withdrawal
• equipment window resource filter visual fixes
• Adds citation counter badges to roster buttons and eligible-first default sort
• Skips medal award confirmation when political power is plentiful

AI

• Indonesian AI is now significantly more likely to win the revolution

Modding

• Added on_actions for admirals when a battle is won or lost
• Added a new trigger: is_fighting_in_strategic_region can be used with a combatant scope.
• Fixed a CTD that could happen in modded content with to small text buffers
• set_autonomy now has a flag to keep the country’s subjects as subjects
• Added is_core_of = ScopedVariable and is_not_core_of = ScopedVariable collection operators (better performance than the trigger alternatives)
• Added IsDeployed trigger for Army HQ and variables state_deployed and province_deployed to unit leaders

Bugfixes

• The popup from the joint Focus trees on the Chinese Warlords now respects allowed branches
• AST: Focus Done Meddling and The Ultimate Overseas Duty has been altered to not release current subjects
• AST: Vichy Out of Africa events (AST_diplomatic_events.58, AST_diplomatic_events.55) tt’s edited to refer to focus Undeniably Ours instead of Done Meddling
• Fixed an issue where the Dutch/Indonesian focus “Fund the ML-KNIL” did not add the mentioned air xp gain
• AST: Leave allied if gone independent as fascist independent Stephensen
• AST: Resolved issue of gaining Sufficient Funds in decisions Australia First Movement twice + Cleaned up the system
• SIA: If you are in a limited war and another country takes control of one of the states that is a part of the limited war you no longer need them to complete the limited war (Japan taking Tonkin while a limited war is ongoing with France for example)
• AST: Idea Singapore Strategy no longer gives on_remove effects if removed due to not owning Singapore
• AST: TT for focus Singapore Strategy requirements now reads ‘Australia: Controls Singapore’ instead of ‘Controls Singapore’
• AST: Minor tweak exchanging Daily PP Cost for Daily PP Gain (same overall effect, just clearer meaning).
• INS: Indonesian General Gatot Soebrotos MHC role is now visible when unavailable, if you have him as a General
• INS: Indonesian focus ‘Oerip’s Army’ now shows a tooltip for the MHC unlocked by the focus
• SIA: Fixed a bug that caused a Siamese spirit to appear for other countries sometimes
• SIA: Fixed a bug where short war would not apply a temp buff correctly upon war declaration, updated tooltip
• INS: Indonesia will now unlock Henri Winkelman’s army chief role after completing the focus “Transfer of Henri Winkelman”
• SIA: added override for Vichy to not be able to join factions after they are the target of a limited war
• SIA: Fixed a broken research bonus tooltip in Reduction of agricultural yield taxes
• SIA: Fixed response events now triggering when demanding to release Laos, Cambodia or Vietnam
• Changed Australian state names.
• Exile Generals will now start at level 1, with level 1 stats (instead of level 1 with level 3 stats).
• Fixed a CTD occuring in some mods when the number of rocket missions where large in an airzone
• INS: Focus “Prioritize the Sugar Economy” will now only target states that are either cored, or owned at game start
• AST: Fixed misspelling of “Kembla” in Develop Port Kembla tooltip.
• Fixed a bug where the Netherlands forming the Netherlands-Indonesia union would block removing De Crisisjaren
• AST: Whyalla Steelworks keeps their logo when upgraded.
• AST: John Brown and Company’s Wartime Surge Capacity changed from Production Efficiency to Output.
• ABDACOM: nations not in the ABDACOM faction will no-longer be able to complete their focuses.
• INS: The East Indies Navy branch can now be completed by Indonesia after forming the union
• AST: Chief of Airforce Charles Burnett’s trait has been changed to a proper CoA one for basegame
• GER: States for Reichskommissariat Australasien has been edited to include new states
• AST: Corrected spelling of Melanesia for Australasia formable
• OOS in comparing tech levels
• An HQ ability being blocked by the Commander being sick or wounded no longer incorrectly says the HQ is undeployed.
• Fixed Second Treaty of Berlin availability vs fascist or non-aligned Soviets.
• Fixed tooltip for already unlocked doctrines display an Insufficient XP warning
• Fixed army HQ deployment time not properly scaling with HQ division size.
• Occupied provinces are now valid options for staging Raids from, fixing the use case of Soviet now being able to stage Rescue-Captured-Commander Raids from occupied eastern Latvia into western Latvia
• OOS relating to characters not being sorted correctly
• Peace conference oos fix
• Correctly handles equipment/manpower for HQ template changes mid-deployment
• The Light Tank Destroyer Regimental Support unit now has the Soft Attack penalty as the rest of TD Regimental Support Units.
• Armored Engineers now provide a proper amount of the breakthrough (+5% to the armored units, instead of a paltry 0.05).
• Trade Interdiction Submarine Milestone Submarine Attack +0.1 got replaced with Submarine: Torpedo Attack +10%
• Marine Commando: Reward 5: Pioneers should now provide proper +15% Armor bonus to the Amphibious Armor

Patch 1.19.3 gives the Thunder at our Gates countries one more round of tools while settling several balance issues from the summer beta. Which change will have the biggest effect on your next campaign? Share your thoughts in the comments, and follow us on X, Bluesky, YouTube, Instagram, Steam, and Telegram for more coverage.