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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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Thanks for the update. Many things to discuss but the one thing that would improve battle planning that is actionable is the ability to launch attacks/gain planning from fallback lines. There are bugs today that can be exploited to allow this (such as invalid garrison orders) but having a real way to say “you three tank divisions sit here in good supply and plan to attack there” would be awesome. Or even if they’re within a few tiles of a frontline order allow trickle planning.

Thanks for the update. Looking forward to the Pacific stuff.

Edit: Trickle planning range would be a great way to buff recon.
 
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Semi-Alt-History is always something i wanted. I guess there will also be presets for the alt-hist-choices then? Like a Central Powers preset where, German Kaiserreich, Austria-Hungary and the Ottomans team up is a reasonable manner and the Allies react in a more suitable way as well. Maybe like an event, so that they will team up then.
 
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Are there any plan to improve the generic focus tree? I'm not asking for a super focus, but at least a better one than the current generic focus tree.
 
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I’m actually a huge alt-history enjoyer, but I can understand why some people don’t like them.
I hope we still get to see some nice alt-history paths.
(Forming old empires is just fun :D. )
 
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This is heartening to hear and I'm eager to learn more from the Dev Corners. I hope we in the community have time and opportunity to shape the content of the DLC. I know that community input is not an order nor is it binding, but there are many informed historians as well as seasoned players who have a lot of value to add. I hope their contributions are reflected in the product at launch.
 
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Light on details, which is unsurprising considering this is the 'tease', but I'm liking the general thrust of all of this. I'm very interested in the doctrine/industrial/diplo changes.
 
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Thanks for the detailed roadmap, Arheo! It's awesome to see how much has evolved and what’s still in the pipeline. Really hyped for the upcoming Asia content and the doctrine reworks, exactly what I’ve been hoping for.
 
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Reserved For Developer Replies~
So I have been playing HOI4 for a few years and have accumulated 4000 hours and 0 achievements (sorry guys its tradition at this point to keep 0 achievements) I have layed out a few idea's for the navy rework that is likely to be out pacific war DLC upcoming.

Mods have it where you use a command power amount based on ur ship, meaning a stack of ships depending on their equipment and stuff stack up to 50 command power, if you exceed the command power your ships will be given massive fleet penalties, therefore for example if you're the USA you will need to split your fleet up into a maximum of around 50 ships per admiral that way you cannot death stack, this needs to happen in HOI4 in the next naval rework in my opinion

Also seeing a more advanced naval option system such as AI japan as they did in real life using a cruiser and 2 destroyers (different throught the war) which would be used to patrol until a fleet of around 30 ships engage another navy on strike force therefore having around 40 ships in total get into a battle, much more easier then having to deathstack 200 ships in a battle and is how the command power for ship situation fits in.

Thirdly fixing the dockyard issue for ships, most if not every mod that overhauls gameplay has it where you can stick up to ten dockyards on capital ships, paradox needs to fix it so they change the IC for ships and also encourage the use of higher tier ships. In real life the US navy would pump out multiple equivalent of tier 3 ships by 1940/1941, we need to see it where they allow up to 10 dockyards on capital ships then also have an incentive to allow higher tier ships to be built as previously mentioned the current meta is to deathstack ships, especially tier 2 battlecruisers throught 1940's.

So by having an incentive to use tier 3 ships and enough dockyards to pump them out on a construction queue would be pretty optimal. Also having the AI do this where they research naval tech more for countries like the united kingdom so by 1942 the UK would pump out good designs on tier 3 cruisers and battleships for example 3 tier 3 battlecruisers and 5 heavy cruisers tier 3. So with that been said stats need to be reworked on ships. We could have it optimised where depending on the game difficulty you select such as regular, elite will pump out better divisions and higher tier ships.

-----------------------------------------------------------------------

Further to this AI behaviour on production needs a rework, many members of the HOI4 community are sick of the templates AI tends to produce and is why we resort to AI mods to make the AI use certain templates. Depending on difficulty you select on the game we should be able to have the AI do specific templates, such as for example 21 width infantry with artillery and anti air support, provide 36W tank divisions using optimal templates which the AI using its production queues prioritise tanks and air rather then just pure infantry all the time.

One major issue is also the AI completely removing production lines losing its production efficiency this is a big problem when I play as germany, go against the soviets they have some 16W tanks with the worst design and only about 4W of that is actually tanks and the rest are motorized, the AIFC mechanic was amazing when gotterdamerung released but the bad division designs usually made it easy to hold off and the AI almost never plans an offensive in any of my games anymore.

So overall if we could get a rework to templates, prioritise air and tanks more often using meta/optimal templates based on difficulty, and also stop building damn air fields in scottland in 1938 AI United Kingdom, we need the AI to focus on prioritisng whats needed for production queues and also when to switch between economies, for example the UK should focus on adding a few dockyards (as mentioned with the tier ships to build in the earlier paragraphs) and have it build military factories at the right time would be amazing.

As well as this we NEED air force generals. we have our main generals, admirals but we DO NOT HAVE AIR FORCE GENERALS! Allow us Paradox to use F3 to assign a general to an "air facility" or something and planes that operate out of them air bases with certain buffs/debuffs then allow a field marshall to oversee a certain amount of planes in an air wing in general to apply buffs/debuffs. Give us air force generals!
 
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I'm looking forward to seeing what the team comes up with in regards to Japan, China, and the war in the Pacific!

I am also interested in seeing what the new naval mechanics will be like- there is alot of stuff that could be done like battleships being able to use their big guns to strategic bomb certain enemy buildings in coastal states/islands.
 
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"It will come as little surprise that South/East Asia is next"... Hmmm, does this include Oceania? If so, this will be my favorite DLC, cause I'm still waiting to play Indonesia fully!!!
And yes, no more "4 different ways to fight in China as Japan" ;)))
///
i don't need it
I dOn't neEd iT...
I NEEEED IT!!!
TANNU TUVA DLC WHEN?!?!?!?!?!?!?!
 
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On War Efforts patches; much of its potential has been wasted having to fix shoddy releases. In fact I see these more of a way to enact damage control than anything else at the moment. It's been a while since I've had a proper playthrough since too many bugs pisses me off. Also, Imo, the small touch up made by the War Efforts on older trees have been hit or miss. I found those made on Canada in particular to have 0 impact on my pre existing view of its focus tree. There was I think 5 focuses added, only one had flavor to it with the rest having a very generic feel to them and I still see Canada's focus tree the same way before those were added (quite antiquated).

But the most important point remains to release higher quality country packs. Without mentioning their content proper the staggering number of bugs in them slows down the game's whole development.
 
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I’m actually a huge alt-history enjoyer, but I can understand why some people don’t like them.
I hope we still get to see some nice alt-history paths.
(Forming old empires is just fun :D. )
I like alternative history paths. But sometimes they are either too boring (Russian Empire) or too crazy (East India Company)
 
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I have my own little wish list. I'd be glad if we got this before HOI5...

- Reworked AI that has a basic understanding of armor and piercing so hard attack and anti-tank finally gets a place in single player mode?
- Reworking artillery so its unique ability to fire at range does make a difference? How about taking away its combat width, but limiting their number?
- Integrating armored cars and mech into the tank designer? You can already build them, but only use them as tanks.
- How about working spearheads in battle plans?
 
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I am so happy hearing that we will be getting not only Asia reworks, but also faction reworks! I have always thought being a faction leader doesn't bring much, but not I can't wait to see what perks one will have! But one thing though, I would like to see partial victories being implemented. For example, if a country declares war on another and has almost won, both of them could try to make a deal, in which the victor does indeed gain land etc, but not everything in the peace deal
 
If we're getting a Pacific war rework the US will need some love.

As of now (this us from a USA player perspective in SP) there are some things that don't work well and that namely is that there is no reason not to skip all but a few islands. Trade convoy warfare is inexistent and Japan doesn't try to get Guadalcanal, so the whole island hopping and isolating bases isn't a thing.
 
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How are the generals that get added to the game chosen? In Gotterdammerung there were quite a few generals that were not added that from my perspective really should have been (von Reichenau and Busch just to name two).