Hearts of Iron IV — patch notes and updates
Stored observation / content update:
Dated developer announcements recorded from Steam. Open the source for the complete update.
| Update | Date | Excerpt / source |
|---|---|---|
| HOI IV Dev Diary | Romania: Military, Country Mechanic & More Alternate History | 2026-11-03 | Salut, Generals! I’m marijn211, and today I will be showing some of the Focus Tree parts I worked on, which comes down to the left side of it, both in in-game positioning and political ideology. First though, I want to show the country mechanic that was shown in our first Dev Corner in a bit more detail. Cooperation Mechanic Here you can see all the countries that are available in the mechanic, Romanian relations with Hungary and Bulgaria were not the best so interacting with them is blocked until you either do certain focuses or end up in a faction with them. Interacting with countries is done in two ways, the tier can be invested in with po |
| Hearts of Iron IV | QoL Patch Notes 1.19.4 (Updated Nov. 5th) | 2026-10-27 | Generals! Christmas is coming a little early this year in the shape of a large War Effort update. Once again we have put emphasis on adding various QoL features we feel improve the Hearts of Iron IV experience. This has been an effort to address some of the outstanding requests we have been seeing over time from our community and we hope you will enjoy them. While there are quite a few things we’ve addressed, we want to do more of these updates that improve the overall user experience to feel more modern than the game actually is (TEN years is a long time…). A lot of you have indirectly contributed to this update by sharing your thoughts with |
| HOI IV Dev Diary | Romania: A Flawed Democracy | 2026-10-22 | Generals! Greetings, I’m Norrman and I’ve been working with Marijn and Alex on the upcoming Romania Focus Pack and I will cover the first part of this Dev Diary. Some quick notes about me before I move on to the content that has been my main focus. I’ve been playing Hearts of Iron IV since about a month after the game’s release and I’ve been modding the game for a bit over 4 years at this point. Starting Situation Now, back to the matter at hand, the Kingdom of Romania! In January 1936, the Kingdom of Romania was practically at the peak of their territorial expansion. Following the end of the first World War and the short war with Hungary in |
| Dev Corner & Open Beta: Energy #2 | 2026-10-07 | Hello again! After a lot of reactions last week, we’ve made some changes. We are still not sure if we should release this or not, but based on the reactions we also decided to make this an open beta. Changes since last dev corner: Power plants now fulfill a state slot instead of the shared factory slots You can build up to 3 levels of power plants in a single state Research has been added, allowing you to gain more energy from the plants Oil now also impacts energy generation. We still want to keep oil focused on being fuel for your army, and coal focused on being fuel for your industry. Introduced a bonus for having spare capacity Added 2 ne |
| HOI IV Dev Corner | Strikes! | 2026-10-06 | Hello there! Your feedback has been much appreciated, both with civil wars and old Canada content. So I come here once again to ask you what do you think about…. Strikes! (As in the labour history, workers striking for better rights) I’m particularly curious about what you feel about the generic strikes (low stability) vs country specific strikes (like Australia’s communist paths) What do you think about the generic strike events? What times do you think country specific strikes have been done A. Well? B. Poorly? And why? And finally some specific questions. When do you, as a player, want to strike? And what do you think the current system(s) |
| Steam Autumn Sale 2026 | 2026-10-01 | Generals!We've received communications from our Allied Headquarters, that indicates Hearts of Iron IV and its associated DLCs will be taking part with the Steam Autumn Sale!Take advantage of this recent development, and secure additional frontlines for the war effort. |
| HOI IV Dev Corner | Energy | 2026-10-01 | Generals! Something different, not planned for any expansion, but perhaps a future war effort. We added coal to the game as part of the free update released with No Compromise, No Surrender. However, coal did not end up where we really wanted it, and we ended up nerfing its effects to the point where it didn't really matter anymore. Part of the feedback we received was that using coal to represent energy did not actually introduce energy production itself: dams and experimental power plants (such as Nuclear Reactors in Götterdämmerung) merely lowered power usage within a state rather than generating electricity. We are now introducing energy |
| HOI IV Dev Corner - Old Canada Questions Before New Canada | 2026-09-29 | Generals!Another week, another Dev Corner. Read through and give us your relevant feedback.Hello all! I'm the content designer working on Canada (obviously the most important nation in the DLC), and I'm well underway but I'd figure I'd swing by and ask you some questions about the existing Canada content: Is there anything in particular you like about it? Is there anything in particular you don't like about it? Is there anything you feel is missing? When you play Canada, is there any specific type of playstyle you like, and if so why? For example, “I love creating an air force and sending them to the UK”, or “I love the idea of being a thorn |
| HOI IV Dev Corner | The Great Depression | 2026-09-22 | Hey, folks! This is your friendly neighborhood ImaginedPanda, content designer on Heart of Iron, coming to you with today's Dev Corner. For our current iteration we will be talking about economic woes or how I stopped worrying and started to love The Great Depression. As you might have gathered from other Dev Corners we are looking at how we do Industrial or Economic gameplay and we on the content side of things are thinking about how we could make the narrative side more historical, interesting and just plain fun. So why not take the biggest economic event in the general time period of Hearts of Iron as a case study? Currently we are using T |
| HOI IV | Patch 1.19.3 | 2026-09-17 | Generals! With the weather becoming more gloomy and the summer on its way out, we bring the last “Summer” release. This will be the last patch that specifically targets Thunder at our Gates and brings a few additional pieces of content for the countries that were introduced with it. This patch also comes with a solid number of balance changes that were introduced from the Open Beta Summer Edition™ that we thought would be good to roll out sooner. The main reasoning for this was that there had been quite a few issues around balance that we did not address before the summer break and we did not want to push them further ahead longer than was ne |
| HOI IV Dev Corner | One if by Land, Two if by Sea, Three if by…Air? | 2026-09-15 | Hi all, and welcome to the next installment of our 2026 Dev Corners. Your feedback on ideas in early development, including my prior ones on army quality and airborne troops, is very helpful to us. I hope I can benefit from your input once more. As you can likely surmise by the content of my previous DCs, I’m a big enthusiast of the history of airborne troops. Really, if you’re into WW2 in even the slightest way, it’s impossible not to be moved by the dramatic image of lightly armed, elite troops leaping into the unknown, bypassing fortified front lines to strike directly at vulnerable points in the enemy rear. The high stakes of such operati |
| HOI IV Dev Corner | Industrial Might & Military Production | 2026-09-08 | Generals! Welcome to an additional Dev Corner on Military Production. Hello, I am Zwirbaum, Game Designer for Hearts of Iron, and welcome to this Dev Corner about Industry. This is a follow-up to the Military Production Dev Corner since you had a lot of feedback around it. We noticed there were a lot of concerns with regards to changing the system and because of that we want to give a bit more additional information to clarify a few things about what we are working on. Everything that you will see and hear today will be subject to change, as there will be plenty of placeholder pink art, (including my wondrous and whimsical art). Content, syst |
| Studio Gold Update | September 2026 | 2026-09-04 | Hello Generals, Admirals and Air Chief Marshals! Swedish summer is over, and we were blessed as it lasted a good 5 weeks. We’d already started work on the 1.19.3 patch before, and we’ve been at work putting the finishing touches for the last several weeks. And while dates are always subject to change our plan is to release that on September 17. Patch 1.19.3 wraps up our active post-release Thunder at our Gates work, it contains a new secret path for Australia & some additional content for late game Siam & Indonesia. Besides that it also contains a plethora of bug fixes & balancing. Next DLC? You may have seen our Romania Dev Corners, and we’r |
| HOI IV Dev Corner | Inlay Windows & Congress | 2026-09-01 | Hello there! Welcome to the next Dev Corner, where we might present something we’re working on or gauging people’s thoughts on mechanics and other things. Those of you who have been keeping up with our trailers, teasers, and dev corners have probably figured out that we’re working on something new, and I’m here to make you folks spill the beans on what you think of certain new additions to the game, and see what we can improve to make them more engaging. Cutting straight to the point, I’m curious what you think about Germany’s Inner Circle and Japan’s Imperial Influence: what do you like, what do you dislike, and what do you feel is missing f |
| HOI IV | Open Beta SE™ Update 3.03 | 2026-08-28 | Generals! Hello, I’m Zwirbaum, Game Designer for Hearts of Iron, and I want to welcome you to yet another Open Beta SE™ (Not really trademarked) Update for Hearts of Iron IV. This week I am bringing more of the experimental features and changes, which may or may not end up in the game integrated into the main branch. That’s why your feedback is important and to let me know how you feel and how it plays with the current set of changes, as well as more of those that are coming. As usual there will be more of my ramblings in the Developer Commentaries in the Patch Notes, and I will be looking at the messages across different platforms, but that |
| HOI IV Dev Corner | Romania, an Industry Divided | 2026-08-25 | Hello all! In today's Dev Corner, we're diving into the economic crossroads of Romania. Like many nations in the 1930s, Romania was torn between its agrarian foundation and a push for rapid industrialization. What makes it unique, though, is the sheer scale of this divide, with over 70% of the population tied to rural agriculture,; modernizing the nation is no small feat. It will be up to you to choose how to balance this traditional landscape with the urgent need for industrial expansion. Breadbasket of Europe With vast, fertile plains, Romania for a brief period of time held the title of the "Breadbasket of Europe." Taking this branch of th |
| HOI IV Dev Corner | Romanian Crossroads | 2026-08-18 | Greetings, generals! We are Alex, Norrman and Marijn211, modders of the game and now cooperating with Paradox, and today we’re showing you tidbits of a future DLC for… Romania! As explained below we won’t go into too much detail yet as not everything is finalized, but this also means that we can optimally incorporate your feedback. Two weeks ago we showed the International Cooperation mechanic that is intended to be the main mechanic shared between all political branches. Everything is subject to change of course, and we’ll keep in mind your feedback like not wanting to constantly maintain it, only to be repaid with insignificant rewards. Mos |
| HOI IV | Open Beta SE™ Update 2 | 2026-08-12 | Generals! Hello, I’m Pdxen, Tech Lead for Hearts of Iron and I want to welcome you to the second update of the Summer Open Beta. In this update we are changing the topic from balancing to updating the tech stack of the game. A lot has happened with computers since Hoi4 was released. Back then, new CPUs used to have 4 cores and around 8 hardware threads, and all of those cores were heterogeneous. All but the lowest end CPUs have more cores and hardware threads today, and not necessarily homogeneous cores anymore. In this update we’re updating the threading libraries used in HoI4, with the aim to improve performance on some machines. Considerin |
| HOI IV Dev Corner | Army Quality and Expertise | 2026-08-11 | Hi everyone, Jamor here again. I want to thank you for good, informed feedback and suggestions in the previous airborne dev corner. I hope I can benefit from the community’s collective insight once more. Up to this point, unit quality across the board in HOI has been fairly uniform: units from different countries level up at a broadly equal rate, and have similar limits on the XP they can gain from pre-deployment training and on-map exercises. Historical differences in military aptitude are largely modeled by static national modifiers, which don’t always allow for broad player choice and alternate history outcomes. Casualties are replaced wit |
| HOI IV Dev Corner | National Focus Flavor | 2026-08-04 | Hello all! Today we're kicking off a new round of Dev Corners, this time turning our attention to a project we haven't touched on yet. We'll start with some early questions around ideas we have in mind, while future Dev Corners here will get a lot more specific about the country and content drafts we'd like your opinions on. Let’s start with some general design questions, just to see what kind of focus tree styles you liked and what you would want to see more of: Do you think focus trees of different countries should interact more with each other, and what sort of focuses? Shared branches are one way to achieve this of course, but perhaps the |
| HOI IV Dev Corner - Military Production | 2026-07-28 | Hello, I am Zwirbaum, Game Designer for Hearts of Iron, and it is once again the unfortunate for you my time in the dev corner spotlight. Anyways, without further ado, let’s get started with today’s topic - Military Production. And once again I will resort to acting a bit mysteriously, while asking some questions. Military Production operates on an abstracted pool of the factories, which means that you can always re-assign your factories to produce something that you need, and regardless of what is happening to your industry, your highest priority of production will be going offline last. - Do you like that system? And if so, what do you like |
| HOI IV Dev Corner | Civilian Economy & Consumer Goods | 2026-07-21 | Hello, I am Zwirbaum, Game Designer for Hearts of Iron, and uncharacteristically for me, instead of writing an entire wall of text, I am just going to ask a couple of questions that are very much tied to the ‘Economy’ side of the gameplay. And those are as follows: How do you feel about the ‘Civilian Economy’ that currently exists within the game - as in anything that relates to the building construction, using civilian factories for trading, laws etc.? - Is there something missing when it comes to the ‘Civilian Economy’? - How do you feel about the current depth of it? - Do you feel that the current system fulfills your immersion of what is/ |
| HOI IV Creator Interviews with Leadership | 2026-07-15 | Generals! High Command is aware that certain war correspondents have, in recent days, taken it upon themselves to question senior staff. Studio Manager Gorion and Game Director Batya were located, escorted without incident down to the Bunker, and placed before the cameras for a thorough round of questioning regarding the future conduct of this campaign. Four dispatches have been filed. Review them ASAP. Dismissed! |
| HOI IV Dev Corner | Warfare in the Third Dimension - Airborne Units in HOI | 2026-07-14 | Hi all, it's time for the next Dev Corner. I'm Jamor. I started as a producer on Stellaris, Imperator, and other games back in 2017, and now I'm happy to be back as a designer on HOI. Hearts of Iron 2 was my first PDS game, and I've had a lifelong obsession with the story of this most fascinating time period in history. It's an honour to be able to contribute to something so close to my heart. One of my goals for a future release is to improve airborne troops in HOI. Although they’ve been in the game since launch, they have a number of practical issues that limit their use: Airborne jumps are queued up by a number of tedious manual steps, fro |
| HOI IV - Open Beta SE™ Update 1 | 2026-07-13 | Generals! Hello, I’m Zwirbaum, Game Designer for Hearts of Iron, and I want to welcome you to the first update of the Open Beta SE™ (Not really trademarked). To avoid writing too much, and boring everyone to the death, as I am fairly sure - you will likely skip to the patch notes section anyways. For those that are not skipping immediately to the patch notes, I want to say thanks everyone for sharing your feedback and opinions, and engaging in discussions with me, that was incredibly helpful! Now this update may contain even more of the highly experimental changes, so stay tuned, and look through the patch notes to look for them. They will li |
| HOI IV Dev Corner | Questions about Civil Wars | 2026-07-07 | Hello all! First of all I want to be extra clear - we are not talking about a rework for civil wars. What I am after is understanding how you’ve enjoyed content with civil wars, what feels good, what doesn’t feel good. So! When you start a game with a country that has a civil war, and you intend to play as that new nation, whether that be fascist UK, Communist Japan - what do you as a player do before the civil war starts? Some questions that may help you along the way: How do you feel when you start progressing down the focus tree? Do you try to rush down the civil war path, do you do common branches? What do you do with your military? (the |
| HOI IV - Open Beta Summer Edition™ | 2026-07-06 | 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 provid |
| Thunder at our Gates | Patch 1.19.2 | 2026-06-30 | Generals! Today marks the last pre-summer patch with fixes and tweaks to Thunder At Our Gates. After this the team will have limited presence in the office for the summer period. We know that this patch does not hit all the sought after balance changes but for that we’d like to refer to you a new Open Beta that we will be running over summer that will address some of those issues. For now, be fully immersed in the rumble in the jungle with the summer heat seeping through your windows. See you all after summer! ROLLBACK For this release we’ve added the option to roll back to our recent Patch 1.19.1. This is useful for players that have saved g |
| Steam Summer Sale | Up to 80% Off! | 2026-06-25 | Generals! ️ Summer is officially here and with it we bring you the latest Summer Sales, including unprecedented discounts. The Steam Summer Sale has started, with discounts up to 80%. Thunder at our Gates just released, did you review all your briefing material? The Official Thunder at our Gates Release Video Missed the Release Stream? Watch The Official Release Livestream here! The Hearts of Iron IV Anniversary Announcement, including a special teaser at the end! Don’t want to wait til the end? Here’s the teaser in full. Even if you can’t engage at work, you can still enjoy the soundtrack (while you count down the minutes.) Hearts of Iron IV |
| HOI IV | Open Beta Weekend (1.19.2) | 2026-06-25 | Generals! We decided it would be best to run 1.19.2 as an Open Beta over the weekend to get some potential player input over the weekend. This will allow us to make any necessary fixes as well that might pop up as a result from having a wider testing net. The upside is earlier patch notes! One thing I want to mention beforehand however is that there are no massive balance changes in this patch at the moment. This does not mean that we are not seeing the flagged issues, and we are aiming to do a wider balance pass, but more on that next week. For now, thank you for the input and stay safe out there. /Batya How to join this Open Beta: This beta |