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Hearts of Iron IV Anniversary Week & Developer Corners!

Generals!

Not only is our nine year anniversary happening today, but we've got a lot of content for you all to read through so make sure to continue reading. We've got Developer Corners starting up again, HOI4 Anniversary Giveaways every day and the Multiplayer Mayhem happening in the 2025 Community Cup!


But first, a word from our Commander in Chief @Arheo .


Greetings all,

As the oft-quoted Eisenhower stated, ”In preparing for battle, I have always found that plans are useless, but planning is indispensable”. In the spirit of this, we thought it would be time to take a look at the long-term roadmap for Hearts of Iron. It has been around three years since our last formal Hearts of Iron Roadmap, and while plans have changed and evolved, this statement of intent has been largely what has guided our development process up until the release of Götterdämmerung.

Our mainline intended innovations, when this was written just after No Step Back, included the following:
  • Improvements to Frontline Stability (Progress in NSB, more to come)
  • Strategic and Tactical AI improvements
  • Battle Planner Improvements
Götterdämmerung included a lot of improvements to the AI including Force Concentration: a feature designed to simulate tactical pushes and armor concentration. This has been an interesting one: when released, we saw a lot of players taken by surprise by the AI using this approach, and a lot more discussion over players being defeated or losing to the new AI behaviour. However, most of the community seems to have adapted fairly quickly to this change. To me this is a positive thing: while having a broad playerbase with varying levels of skill means we need to be gradual about how and if we increase overall difficulty when playing against AI, the existence of community “meta” and learning materials gives most players tools to catch up. In short, there’s no reason not to continue iterating on AI features that may increase average difficulty or required skill levels.

On a related note, we’ve fixed a bunch of issues with frontline stability, but battle planning remains a tool that has a stark divide between how new and veteran players utilize it. We’ve done some quite deep user research into this particular area, but this resulted in few actionable results beyond handling edge cases better and improving frontline integrity.


Long Term Goals and Strategies to guide AI (Progress in NSB)

Most of this is “under the hood”, but we’ve made a lot of progress adding tooling to interpret and direct how the AI performs long-term planning. This area of the game is notoriously opaque and it’s taken a fair while to get to the point where we have enough analytical insight into the mechanical decision-making process of the AI, but, we’re more or less there now. This has meant improved tooling such as AI strategies, imgui debug tools that modders also have access to, and better integration with existing mechanics that previously existed “on top” of the game without interacting much with the AI. This is of course a goal that has no defined end-point, but compared to where we were three years ago, much has improved.


Improving Peace Conferences

By Blood Alone saw a contribution-based peace conference system added, with numerous narrative demand options. On reflection the design approach here was not super stable, and while the feature hit most of the key notes (contesting demands, earning defined contribution, rewarding better play), it fell into a similar trap to the old system when it came to AI antagonism. It took longer than it should have done for that behaviour to stabilize with tweaks and changes, but we’re in a better (if not perfect) situation now.


Update Core National Focus Trees with Alt-History paths alongside more Options

We’ve had a couple of methods of doing this. First are the maintenance updates included in some War Effort patches. These tend to be quite minor, but we’ve added a fair few things to various focus trees over time.

Secondly, revisiting focus trees such as Germany and Hungary represents a greater investment into this. Overall, I’m happy with the dual-pronged approach to this; reworking focus trees comprehensively is a full expansion-cycle affair, and doing it outside of a paid release is not something we will ever be able to do. I feel the majority of the community understand this, and our roll-in approach to DoD, TfV and WtT has been for the most part welcomed.


Great Power Diplomacy

I’ve spoken at length on this in a few other places. Fundamentally, design ideas for this one always ended up conflicting with focus trees. HoI4 is a war simulation with a superimposed latch-driven state-machine that drives the global narrative. It is unlikely we’ll change that approach. However, the process of working through design ideas for this has given us some avenues for further exploration.


Multiplayer & Social layer Improvements & Support

The Career Profile and associated features hit the social layer note pretty well. Traditionally, these features are designed to increase player engagement: something which HoI doesn’t really have an issue with. However, the feature has proven to be unexpectedly popular amongst specific groups within the community, both for completionists and as a learning aid. While I don’t think we’ll be making any fundamental additions to this, it won’t be going away and we’ll keep adding content such as new medals and ribbons.


Economic Decision Making

We haven’t made any great strides here. We still have medium to long term plans to expand the industrial economy elements of HoI, while taking care to avoid simulating too many pure economic elements.

Special Projects

Götterdämmerung represents the culmination of this project. I’m pretty happy with how this turned out, though now that we’ve had some time to monitor the wider effects of special projects, it is about time to revisit balance and take a pass on the huge array of tech that was added in the Götterdämmerung update.


More Difference between sub-ideologies & Government forms, Advisors and Internal Politics Improvements

We didn’t really get here! This is quite a difficult topic to broach in a strategy game, and other things ended up taking precedence. We’ve had some minor changes to advisors, but nothing to write home about in the grand scheme of things.


More National Focus Trees

Fairly Self-explanatory.


Make Defensive Warfare more fun

This is still a goal of mine, but we haven’t managed to tackle it yet. I think some of the fundamentals of HoI4 (ie, stuff we simply can’t/won’t change) stand in the way of doing this justice, though it also plays hand-in-hand with changes to doctrine and division design which are definitely in the works.


Adding Mechanics to limit the size of your Standing Army, Particularly post-war etc

Definitely still planned, though not a major priority on its own - will have some words on this later. I don’t feel like this is something that has been glaringly missing for a game with a narrative of “crescendo to war”, though as we start to experiment around the fringes of that pillar (smaller regionally-focused conflicts and expansions), it will become more necessary.


Have Doctrines more strongly affect Division Designing

We’ve had some success here with the changes to support companies and equipment streamlining. I wouldn’t go so far as to say this is “done”, though. We have short-medium term plans regarding doctrines though, and having them affect division design more strongly is one of the key pillars for this effort.


Immersion and Roleplay Elements, Optional tools for making your mark in a game

We’ve added a lot of things that touch on this: division medals, plan naming, deeper recruitment design, MIOs and industrial specialization being chief among them, feature-wise. I think these features do what they set out to do: letting you leave your own mark on the battlefield and the campaign narrative. As you may have noticed from recent war effort patches, we’ve also identified that we need to be better with streamlining how players interact with these types of features.


War Effort Updates

I talked at length in the 2022 roadmap about the introduction of maintenance updates - something we ended up doing, and calling “War Effort” patches. On their own merit, these have been extremely useful for us, and have allowed us to iterate and introduce quite a lot of system updates and quality of life changes such as:
  • Persistent equipment designs
  • System Rebalances to designer modules and units
  • MIO streamlining
  • Some quite significant performance improvements
  • Over 1000 bugfixes
  • Mod support
  • Focus tree updates
  • Balance standardization of some systems (quite important for game health!)
One of the things we were uncertain of before we started War Effort patches was whether this would reduce the maintenance included in major updates, resulting in effectively just moving things around. With the exception of our approach to country packs (ie; not including maintenance updates at country pack release), it has not directly affected the size and impact of major releases.

The old Roadmap championed these as a method of updating older focus tree content. It’s fair to mention that this ended up not being a major focus of war effort updates. It became quickly apparent that developing focus trees is the majority of the work our Content Designers do; that’s not realistically something we can do in iterative updates.

So while there is success here, there’s also room for improvement. We will keep producing War Effort updates, but I want to try and find some form of structure to them, and a way of steering them in a way that more quickly addresses high impact community issues. Particularly, I would like to find a way to increase the visibility of our approach to handling community issues, though I will caution that this will require some time to achieve.


Next Steps

Aaand that’s our retrospective.

That ended up quite a lot longer than I’d expected, but that’s ok - the future plans are at least a little more concise! I want to give you an updated roadmap for our next few years, though with the usual caveats. As you can see above, these plans are not super specific, they aren’t promises, and they don’t always work out. Nonetheless, the act of planning is extremely important, and communicating those plans perhaps even more so.

So what does the future look like for HoI4?

It will come as little surprise that South/East Asia is next, with content primarily focused on Japan and China, and mechanics to support this narrative, as well as reinvigorating the Pacific war. I don’t want to go into too many specifics here (tune in next time for more!), but the war in and around Asia as well as the Pacific has been left behind by our recent developments directed at the European elements of the conflict. To give some broad strokes here, we’re looking at developing the narratives that faction membership will give you, improving and streamlining elements of naval control, with a particular focus on the types of naval warfare that carried the Pacific conflict, and adding much greater strategic narrative (and a less opaque simulation) to the flow of naval conflict. This is not an exclusive list, and it’ll probably leave you guessing - but you won’t have to wait long.

In the longer term, we have some other areas that we’re keen to take a pass on:


Military Doctrines and Division Design

These systems are quite old and don’t offer much ability to shape your gameplay. I would like to link these better, in order to have doctrines shape both how you compose and how you use your military.

Manufacturing and Industrial/Economic Gameplay

Watch this space.


Breaking the Snowball!

HoI’s “crescendo to war” that I mentioned earlier is extremely important to the main narrative of the war. However, as time goes on we have released more content focusing on the smaller players in this conflict. There are elements of the game that don’t mesh particularly well here, and I want to take a look at the way wars and war escalation are structured to make this more engaging and less disruptive when minor conflicts erupt.


Improving the Diplomatic Landscape

“But you said you couldn’t do this!”, I hear you cry. And mostly you would be right. However, with the introduction of late game technologies in Götterdämmerung, there is even more reason to continue playing after the end of the war. I would like to keep developing how the world “falls out” after the conflict, producing more realistic geopolitical results as well as the potential for new and more systems-driven “what if” conflicts after the end of the war. Of course, any such changes would be multiplied in effect if they could also touch upon the pre-war landscape too…


Alt-History

Well, that’s a broad category. This is one we’ve been looking at in quite a lot of detail. We see an increasingly stark divide within different groups of the community on how we (or even if we should) approach alt-history. For those that enjoy it, don’t worry, we’re not going to stop making alt-history content, however, I have asked the team to look, in the long-term, into ways of producing more structured, plausible alt-history content with clearer historically-adjacent narrative hooks. In addition, we have started to evaluate if it’s possible to create more deterministic global alt-history situations and produce some “semi-alt-history” ways of playing HoI - something that I think would capture the fun parts of the non-historical content we provide while also retaining the benefits of the determinism that the historical scenario imparts.

I have one, final note on the practical elements of what we release. We intend to continue releasing what we’ve previously termed “Country packs” and “Unit packs”, but we need to both be clearer about what is or isn’t included, and adjust the scope. We’re devoting some more resources to our Country pack development moving forwards, and we’ll be including mechanics and systemic changes in those the same way as expansions - albeit still focusing on “minor players” in the war.

Alright, I started writing this three hours ago and apparently I’m still going, so here I will force myself to stop. I’m here to answer questions.

/Arheo


Hearts of Iron IV Dev Corners 2025 Roadmap - Updated: June 16

Of course, these dates may be subject to change so keep that in mind!


Hearts of Iron IV's 9th Anniversary!

As apart of HOI IV's Ninth anniversary, we've decided to do another giveaway with a different prize each day including some fan favourites and some keys for the new Song pack for those of you who missed out on some of those banger tunes. To participate and enter for a chance to win some of these codes, make sure to reply here on each day you want to take part in the giveaway.

Because of time zones, we've decided that each giveaway "day" will start at 14:00 CEST, so for example, if you want to take part in the Bonus Songs Pack giveaway on Tuesday, then you need to reply between 14:00 CEST on Tuesday and 13:59 CEST on Wednesday. If you reply on Wednesday 14:00 CEST, then you're taking part in the Wednesday giveaway, etc.

You can reply as many times as you want, on as many days as you want, but if we're looking through replies and have to choose between two replies, we will probably choose the reply that has some substance (vs "Just replying to take part") so be creative, engage, comment on the announcement or on others' replies.
(Giveaway T&C attached below)

Today: HOI IV Starter Edition So you can play with more friends x30
Tomorrow: Bonus Songs Pack To listen to, even when you're paused x30
Wednesday: No Step Back To bring Communism to the world x30
Thursday: By Blood Alone Take your fight to the skies x30
Friday: Arms Against Tyranny To bring the fight to the Nordics x30

Hearts of Iron IV Anniversary Sale!

To add even more fun to our anniversary celebration, the Hearts of Iron Sale (up to 70% off) is now live over on paradox.com!

Community Cup 2025

We are back for yet another round of the Community Cup, hosted by Dankus. This year, the Teams are participating for a chance to win 5000 Euros! With Casters such as Dankus themselves, Mo and one of our own Community Ambassadors Fraser, the finals will be played June 7th at 17:00 CEST.

Make sure to catch all of the action over on Dankus's Channel, or the HOI Youtube Channel!
 

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Would the next update fix ridiculous oversize of Ryukyu, Iwojima, Palau, Guangzhouwan and Hongkong?
I think gameplay availability trumps accuracy, considering how important those territories are.
 
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Entry for GIVEAWAY.

I genuinely thought to participate you HAD to post in the steam announcement, but I really don't know at this point. I am way too late to get No Step Back, which is a shame. But I suppose I'll just post here.

Heya Paradox, I had to login to the Forums just to participate in the giveaway. Being a player since one or two years ago, I've always wanted another DLC besides Waking the Tiger, Together for Vi.. and Death or Dishonor. I got those from starter-pack, which surprisingly is the same price as base HoI4 when I first bought it. AS always, I'd like to be considered as a candidate to receive any DLC that would be today. Wednesday. Looking forward
 
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Great to see that Japan and China are getting expanded content.

improving and streamlining elements of naval control,
Might I suggest a naval mission that attacks all available targets similar to the general air superiority mission that attacks all enemy planes? Right now, I can patrol or strike force to attack enemy navy or convoy raid to atttack convoys but I can't target both.

I also echo the need for the number of support company slots in a division to be increased to keep up with the new support companies added over the past 9 years (wow, what a milestone).
 
I'm really curious about if there will be more focus trees to the Japan/China rework. Philippines, Siam, British Malaya and Dutch East Indies perhaps? Or maybe even USA? I guess Mongolia and Tannu Tuvu could also be a very interesting bonus.
 
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[giveaway entry]
"Water. Land. Air. My grandmother used to tell me stories about the old days, a time of peace when the lack of any Designer kept balance between the Water Tribes, Land Kingdom and Air Nomads. But that all changed when the Water Tribes attacked... and we had to Man the Guns. After that, the ruthless Land Kingdom took her piece, but we made No Step Back. Only By Blood Alone will the Air Nomads survive".

P.S. HoI4 console edition when?
 
War participation should be increased for naval combat.

Currently, the system heavily favors ground combat, occupation, and inflicted casualties.

This means that if I focus on achieving naval dominance, I receive minimal recognition unless I also land troops.

The most disappointing part is that I can save my allies from enemy invasions by sinking convoys but I gain no war participation at all.

Assigning appropriate weight to each sunk convoy would be a great improvement to the war participation system.
 
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I bought this game on release and although at first I still preferred HOI3, over the years I have really come to enjoy HOI4 and it has probably become my favourite game. I particularly loved the supply update, that added a lot of extra depth to warfare. That's why I'm most excited for the new island warfare update because, as others have said, at the moment it just feels a bit too easy to skip past the islands in the pacific war. Definitely looking forward for that theatre to have extra depth (pun intended)! Just as I am looking forward to getting the By Blood Alone DLC (if I were to get chosen of course) ;)
 
I bought (yes, bought :( ) Man The Guns, but I still don't understand naval combat to make the most of it. By Blood Alone access would offer me the plane designer, which I know are those things in the sky. So I'm hoping to get it now.

Also, I think BBA was the first expansion released after I got the game. I remember really liking the trailer and then at the end BAM you get Verdi, which fitted the theme perfectly.
 
Giveaway entry.

Remember old Italian focus tree? A focus tree where you could bypass 1/3 of the focuses, and where War in Ethiopia would last until 1939, and when you joined ww2 you had gigachad generals. I polished most of HoI4 on that tree. But I love the new one, especially the naval branch, people usually underestimate Italian warship designs and navy, Italy actually had the 4th largest in the world, and had great ship designs, They were flawed with the lack of radar, some ships did get radar systems, some were from Germany, and some were prototypes that were pulled from the storage houses, but the effort would be stopped by armastice with allies.
I had many fun campaigns as Italy, most of them tied to the navy, and the reclamation of Mare Nostrum, chasing the British warships in the Mediterranean, and them chasing me back, actually feeling that deploying another pair of heavy cruisers will matter, and struggle to keep up destroyer production. Breaking through Suez into Indian Ocean to try and link up with Japan and help fight the USN.
Or failing miserably by having one bad naval battle, and then trying to nurse back up, to replace losses, to try and trick the British, to gain an edge in the long war under the Mediterranean and African sun. Trying to catch a smaller British fleet in an ambush, and using asymmetrical warfare to keep reinforcements away. Both sides giving each other small cuts in the shape of convoy raids, trying to bleed one another. The North African front moved back and forth many times. Trying to push the enemy out of their supply hubs, outrunning the logistics, and overextending, just to be halted on the gates of a crucial port and supply hub, then being pushed back to yours, and repeat.
After a large but still indecisive naval battle, scrambling all available bombers you have to try and score a victory, to at least keep the enemy in drydock for few more days. Because you know that after the Giant wakes, the line will move away from the African and Mediterranean and be drawn closer to the old country.
I guess I didn't really say why I want to get the DLC, but I just love playing Italy.
 
Regarding defensive warfare improvements, would the dev team consider changes to fallback lines? I've found that the existing system can make it difficult to retreat in good order, and divisions will attack to retake part of the line, which I understand, but its usually not what I want to do. I think it would be neat if there was a system for falling back that mirrored offensive line orders, where you draw it backwards from the front and then can execute the plan on any of the three levels of aggressiveness to allow for a slower, more orderly withdrawal than fallback lines currently allow.
 
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I think you're forgetting the most important thing that multiplayer needs: unique usernames. This will help prevent trolls/cheaters from repeatedly ruining games since hosts will be able to blacklist and recognise them.
 
Giveaway entry.

Remember old Italian focus tree? A focus tree where you could bypass 1/3 of the focuses, and where War in Ethiopia would last until 1939, and when you joined ww2 you had gigachad generals. I polished most of HoI4 on that tree. But I love the new one, especially the naval branch, people usually underestimate Italian warship designs and navy, Italy actually had the 4th largest in the world, and had great ship designs, They were flawed with the lack of radar, some ships did get radar systems, some were from Germany, and some were prototypes that were pulled from the storage houses, but the effort would be stopped by armastice with allies.
I had many fun campaigns as Italy, most of them tied to the navy, and the reclamation of Mare Nostrum, chasing the British warships in the Mediterranean, and them chasing me back, actually feeling that deploying another pair of heavy cruisers will matter, and struggle to keep up destroyer production. Breaking through Suez into Indian Ocean to try and link up with Japan and help fight the USN.
Or failing miserably by having one bad naval battle, and then trying to nurse back up, to replace losses, to try and trick the British, to gain an edge in the long war under the Mediterranean and African sun. Trying to catch a smaller British fleet in an ambush, and using asymmetrical warfare to keep reinforcements away. Both sides giving each other small cuts in the shape of convoy raids, trying to bleed one another. The North African front moved back and forth many times. Trying to push the enemy out of their supply hubs, outrunning the logistics, and overextending, just to be halted on the gates of a crucial port and supply hub, then being pushed back to yours, and repeat.
After a large but still indecisive naval battle, scrambling all available bombers you have to try and score a victory, to at least keep the enemy in drydock for few more days. Because you know that after the Giant wakes, the line will move away from the African and Mediterranean and be drawn closer to the old country.
I guess I didn't really say why I want to get the DLC, but I just love playing Italy.
Same here! I learned to play with Italy, I love its playstyle and playable paths, and I would like to try the Pope path. Switzerland and Ethiopia look like fun challenges to play, and I'm highly interested in the plane designer, but I want this DLC the most for the peace treaties: I want the Royal Navy for myself when I conguer GB. And sink the ship that sunked more of my ships:D
 
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can we please have a template designer for armoured cars and mechanised, trucks even but definitely armoured cars, make them more impactful, also since Asia/ Pacific is going to be the focus. I'm excited since i've done some playthroughs as Australia, Dutch East Indies and British Malaya, can be fun at times, just lacks the flavour compared to Europe. i want Asia/ pacific to not be a sideshow . Japan needs the rework but can Australia be updated one day, i believe there's a fanbase with Australia but the focus tree/ flavour is from Together for Victory which makes it severely outdated and lacks a lot of things that modern updates/ latest dlcs have done to other countries. New Zealand is the same, but i'd say a bit worse , If Australia can be a top minor power in allies, supporting in Asia and Europe/ Africa , then New Zealand can be similar but it can be a minor power that can punch above its weight just like Finland and Bulgaria, don't underestimate the Kiwis. British Malaya would be awesome. Fall of Singapore was a major blow alongside the loss of British warships such as sinking of Prince of Wales. Philipines and China of course would have a fanbase. despite most people i'm sure play as Germany or other top European nations. I think Pacific theatre if done right can become popular , also USA shouldn't have to go to war with Germany, remember man with silly moustache declared war on usa thinking that japan would earn his respect or something since those two went to war after Pearl harbour, this could be into play with faction dynamics. also league of nations and potential UN could be a cool aspect in a game. Anyway i've typed enough , but i have high hopes, don't rush things , just create these projects with love and interest, just don't make alt history path too unrealistic though, just remember the graveyard of empires feedback. Also back to Australia, the citizen military conscript forces were nicknamed Chocolate soldiers since they were inexperienced compared to australian imperial force so conscripts were mainly in New Guinea
 
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