Hearts of Iron IV HOI IV | Open Beta III Patch Notes (17th April 2026)

Generals!

Open Beta

Open Beta 01

Open Beta Update 02

Generals!

Best to leave your feedback for this specific beta version in this thread. Bugs go in the bug report forum. You can also start a separate thread, just make sure to reference this open beta and mention something like [open beta] in the title.

I’m Zwirbaum, Game Designer for Hearts of Iron, and after a brief interruption last week, we are coming back with another update to the Open Beta. My ‘internal’, initial idea for Open Beta was to run until the release of Peace for our Time, and with the release date announcement this time seems to be coming to the end, as next week's Friday will be already after the release of the Focus Pack. This, however, doesn’t mean that this week can’t have some fixes and updates - for more details you will have to delve into the patch notes.

With PfoT releasing next week, what does that mean for this Open Beta? As I mentioned earlier, while I initially thought to have this beta run until now, as you’ve seen there were some wrinkles along the way. One week saw no update at all, and for ~two weeks most of my focus was devoted to the Submarine Visibility Changes, making sure that they would be left in a more acceptable condition. I also realized that the weekly cadence of the updates, while trying to do my normal responsibilities + wanting to interact with the community, and engage in conversations about the feedback, having to write the dev diary and making actual changes for the beta put me in, what you might call, a bit of a time crunch.

Why am I writing this? While my intent was to ‘wrap up’ this beta, I will see whether it will be feasible to update this Open Balance Beta after next week’s release - to include Peace for Our Time as well as the patch 1.18 (so instead of this beta being ‘fork off the last 1.17.5.2’, being ‘fork from 1.18’), and we may see some updates to this branch moving forward. However if they do happen, they will likely operate on a less frequent basis (maybe two weeks cadence as that should be easier for me to slot the time for it). Anyways, I am curious to hear whether you would want to see this Open Beta to be updated and exist as the fork from 1.18.

And that is pretty much all from me, at this time.

Thanks for reading, and until next time, farewell!

/Zwirbaum

If you want to join the Open beta, but are unsure how to, check out the steps that are covered in the very first Open Beta announcement HERE

This beta client is Musketeer v1.17.5.2.446d (3124)

• Naval Dominance Factor for Advanced Destroyers increased from 40 to 42
• Coastal Defense Ship Max Strength (HP) increased from 100 to 110
• Early, Basic, Improved, Advanced Heavy Ship Hull Fuel Consumption reduced from 67 to 60
• Early Heavy Ship Naval Dominance Factor increased from 300 to 325
• Modern Heavy Ship Hull Fuel Consumption reduced from 80 to 72
• Super Heavy Ship Hull Fuel Consumption reduced from 75 to 68
• Converted Battleship, Basic, Improved and Advanced Carrier Ship Hull Fuel Consumption reduced from 87 to 70
• Converted Cruiser Ship Hull Fuel Consumption reduced from 87 to 60
• Escort Carrier Ship Hull Fuel Consumption reduced from 87 to 50
• Modern Carrier Ship Hull Fuel Consumption reduced from 90 to 72
• Ice Carrier Ship Hull Fuel Consumption reduced from 95 to 90
• Improved Carrier Ship Hull Naval Dominance Factor increased from 300 to 325
• Light Ship Engine III - Fuel Consumption lowered from 10 to 9
• Submarine Ship Engine II - Now reduces the Submarine Visibility by -3.5%
• Submarine Ship Engine III - Submarine Visibility Reduction increased from -5% to -7% and reduced Fuel Consumption from 10 to 9
• Submarine Ship Engine IV - Production Cost reduced from +20% to +17.5%
• Submarine Nuclear Engine - Now reduces the Submarine Visibility by -15% and increased Naval Speed from +10% to +20%
• Cruiser Ship Engine I - Production Cost reduced from +15% to +12.5% and increased Naval Speed from +20% to +25%
• Cruiser Ship Engine II - Production Cost reduced from +17.5% to +15%
• Cruiser Ship Engine III - Production Cost reduced from +20% to +17.5%
• Cruiser Ship Engine IV - Production Cost reduced from +22.5% to +20%
• Heavy Ship Engine I - Production Cost reduced from +17.5% to +12.5%, increased Naval Speed from +20% to +25% and increased Fuel Consumption from 20 to 22
• Heavy Ship Engine II - Production Cost reduced from +20% to +15% and increased Fuel Consumption from 25 to 28
• Heavy Ship Engine III - Production Cost reduced from +22.5% to +17.5% and increased Fuel Consumption from 30 to 34
• Heavy Ship Engine IV - Production Cost reduced from +25% to +20% and increased Fuel Consumption from 35 to 40
• Carrier Ship Engine I - Naval Speed reduced from +30% to +25% and increased Fuel Consumption from 12 to 16
• Carrier Ship Engine II - Naval Speed reduced from +40% to +35% and increased Fuel Consumption from 16 to 24
• Carrier Ship Engine III - Naval Speed reduced from +50% to +45% and increased Fuel Consumption from 20 to 32
• Carrier Ship Engine IV - Naval Speed reduced from +60% to +55% and increased Fuel Consumption from 24 to 40
• Naval Sub-doctrine Coastal Mine-laying 'Clearing Procedures' reward no longer applies bonus to mine sweeping to the Submarines, instead the effect on Destroyers have been increased from +20% to +25%
• Long Range Submarines Sub-doctrine 'Ocean Patrols' reward now also apply +10% bonus to the surface detection to the Nuclear Submarines
• Long Range Submarines Sub-doctrine 'Improved Dive Protocols' reward now also reduces Surface Visibility of the Nuclear Submarines by 5%.
• Long Range Submarines Sub-doctrine 'Support the Surface' reward now also apply +10% bonus to the Torpedo Attack and Naval Speed to the Nuclear Submarines
• Support Ships and Improved Support Ships no longer have 1 Sub Detection and 1 Depth Charges
• Support Ship and Repair Ship Max Strength increased from 25 to 30 and Range was increased from 3000 to 3500
• Improved Support Ship and Improved Repair Ship Range was increased from 4000 to 5000

Bugfix

• Screening Efficiency Effects are now applied based on the Efficiency Value, instead of being applied at full effect as long as you had > 0% Screening.
• Note that Convoys and Carriers use ‘Combined Screening Efficiency past Battleline’ - and as such, they can get ‘some’ benefits from the regular Screens and the Screening Efficiency provided by them. This may get a second look in the future.
• Carrier Stance Settings should apply now to the first 24 hours of the Naval Combat, and not based upon each Carrier joining the Naval Combat. This meant that reinforcing carriers, such as from the Strike Force, were previously bound to the Carrier Stance settings for the first 24h since their joining of Naval Combat. This should make the Carrier Stance settings and effect a bit more predictable.

UI

• Ship Designer as well as the Ship Card will now display Hit Profile ‘stat’, which when hovered upon will state what is the ‘Unmodified’ chance to be hit by the respectable Attack Types, Light Attack, Heavy Attack and Torpedoes for Surface Ships and Depth Charges for the Submarines.
• Note that when using base game defines, unmodified hit chance based upon hit profile will never be higher than 10%, but can be lower than the currently set minimum hit chance. Minimum hit chance ‘clamp’ is applied at the end of the calculating hit chance, after taking into account effects and modifiers.This addition is not translated to the other languages yet.
• Naval Minelaying and Naval Minesweeping Stats are no longer displayed on the Ship Card if their value is 0.