PATCH NOTES
HOI IV - Open Beta Summer Edition™
Hearts of Iron IV · by PDX Per · Jul 6, 2026 12:17 PM UTC
Generals! Greetings from sunny Stockholm to everyone, I’m Batya, Game Director for Hearts of Iron. The summer period is upon us and I wanted to share some information with you all. Unlike the norm of armies planning summer offensives, game developers actually do the opposite and take time off. Of course I am not here to just tell you we will be out for the summer, instead I want to talk about the Open Betas we’ve been running in the last few months. Some of you might have seen, or even opted into, the betas that we ran for Naval changes and also the Anniversary patch. First of all a big thank you to everyone who involved themselves and provided feedback. It is important for us to co-operate with our community to make a better game and that is exactly what we want to do more of. I’d like to introduce another beta initiative codenamed ‘Sommarfältprov’, which mainly aims at re-balancing different parts of the game. One of the bigger ones has been, for example, Regimental Support that did not entirely hit the mark balance wise. Some other ones are (Sub)Doctrines as well as the long and arduously discussed Line Artillery. These are all things that we want to take a stab at for the betterment of the game. The person spearheading this over the summer-y period will be Zwirbaum and he will be the main person to inform about changes happening on that branch. He will also fill in a bit more on what to expect so I will happily hand over the proverbial mic to them. Have a wonderful summer y’all! /Batya Hello, I’m Zwirbaum, Game Designer for Hearts of Iron, and I want to welcome you all to this new Open Beta, Summer Edition™. Similarly to how we had Open Naval Balance Beta run during the Spring, where efforts were mostly focused on adjusting the balance and fixing some of the issues for the naval aspect of the gameplay, this time I will be taking a bit broader look across the game balance and some of the pain points of Hearts of Iron IV. What is changing for this Open Beta Summer Edition™ - as opposed to the Naval Balance Beta? During the spring I found out that trying to keep up with the weekly update cadence on top of my regular responsibilities, was imposing too much of pressure on me, which meant that I had a bit less time to think about certain things, respond and participate in the discussions with the community and to proceed with the actual implementation and changes. This time there will be no guaranteed or any REGULARLY planned update cadence. Also as we are entering Summer period, there is a small chance that my posts may be a bit more irregular in what they would contain, in order to keep it vacation themed somewhat. So less lengthy posts, with a lot of dry information, but either more concise posts, or a bit more unusual content? This time we may also have more experimental changes that will take more time to reach full maturity. What is not changing from the previous Naval Balance Beta? Once again there is no guarantee that this Beta will be integrated into a main version, when or in what form it would happen, not to mention that it would of course depend on the feedback we would be getting from you, our dear community. For more comments on what is changed, and why, check out for the developer commentary in the specific sections in the Patch Notes. Thanks for reading, and until next time, Farewell! /Zwirbaum How to join this Open Beta: This beta client is Operation Postern v1.19.2.0.40eb (f387) To install Open Beta client, follow the instruction below:
Open Beta Summer Edition™ NotesGameplay
- Right-click the game in your library
- Select Properties from the drop-down menu
- Select Game Versions & Betas
- Select the beta branch called open_beta
Open Beta Summer Edition™ NotesGameplay- 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.
- 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
- Combat Bonus from division experience decreased from 25% to 20%. Green Divisions now have -20% Combat Penalty, Trained have 0%, Regulars have +20%, Seasoned +40% and Veterans have +60%.
- Air Crew Surveys Air Spirit Mastery gain for individual tracks got combined into Air Doctrine Mastery gain Factor.
- Dive Bombing Air Spirit CAS Design cost reduction got replaced with +15% Strike Aircraft Mastery Track gain Factor.
- Material Destruction Air Spirit Medium Airframe Design cost reduction got replaced with +15% Medium Aircraft Mastery gain Factor.
- Industrial Destruction Air Spirit Heavy Airframe Design cost reduction got replaced with +15% Heavy Aircraft Mastery gain Factor.
- Increased naval targeting values for naval bombers for fully screened capitals from 10 to 15
- Increased naval targeting values for naval bombers for fully screened carriers from 10 to 25
- Continuous Strike Air Spirit - Air Support Efficiency bonus has been reduced from 25% to 15%.
- Massed Strike Air Spirit - Air Superiority Effect has been increased from +5% to +10%
- 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 now requires 24 equipment pieces from the previous 20
- Motorized Anti-Air now belongs to the Anti-Air Unit Category
- Anti-Air Unit Category has been renamed to Anti-Air Artillery Support & Line
- Anti-Tank 1940 Technology no longer provides randomly Motorized Anti-Tank with +10% Piercing and +10% Hard Attack
- Light, Medium, Heavy and Modern Self-Propelled Artillery Combat Width increased from 2 to 3
- Naval, Land and Air Facilities cost has been lowered from 12000 to 10000. Scaling cost per facility has been increased from 5000 to 6000. This means that the first and second will be cheaper (10000 and 16000 vs 12000 and 17000) . The third one will have the same cost, while starting with the fourth of the same type, they will become more and more expensive. This should make entering the world of Special Projects easier for smaller & less well developed nations. Nuclear Facility will remain at the current premium cost for now.
- Improved Amphibious Designs now reduce Amtrac production cost by 10% instead of 15%
- Helicopter Brigade and Helicopter Logistics now will have a proper Fuel Consumption instead of having -100%
- 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 to -60% from -80%
- 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%
- TD-RS and SPAA-RS: Artillery Technologies impact on them for Hard Attack and Air Attack has been lowered by half after the full tech tree progression (From +30% Hard / Air Attack on them lowered to +15%)
- 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 have Defense boost from the Technologies.
- Artillery, Motorized Artillery, Rocket Artillery, Motorized Rocket Artillery, Truck Drawn Rocket Artillery, Anti-Tank, Motorized Anti-Tank, Anti-Air, Motorized Anti-Air Max Strength increased from 0.6 to 0.8
- Artillery Equipment I stats have been adjusted to provide following stats: Soft Attack +1 (from 25 to 26), Defense +1 (from 10 to 11), Breakthrough +4 (6 to 10)
- Artillery Equipment II stats have been adjusted to provide 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 have been 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 stats have been adjusted to provide 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 stats have been adjusted to provide 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 stats have been adjusted to provide following stats: Defense +1 (from 15 to 16), Breakthrough +8 (from 12 to 20)
- 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 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 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 removed from the reward
- 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-RS
- Armored Infantry Support 5 Reward: Air Attack reduced to +5% and removed Organization Bonus
- Mobile Defense 3 Reward: Air Attack for SPAA-RS 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 other benefits than the Organization were removed for them.
- Mission Type Tactics Adoption Bonus: Daily Command Power gain has been increased from +0.02 to +0.2