Hearts of Iron IV HOI IV - Open Beta Update V Notes (13th May 2026)
Paradox drops Open Beta Update V for Hearts of Iron IV before heading on a short break, bringing AI naval reworks and a fix for 1000-ship performance tanks.
Paradox squeezed in one more update before taking a short break. Open Beta Update V for Hearts of Iron IV is live now under the open_beta branch, versioned as Case Green v1.18.1.0.9197, and the team is asking players to leave feedback while they're out.
The headline work is on the AI's naval behaviour, which has needed attention for a while. Italy's naval equipment gets an extensive rework, the AI will now train ships more consistently, and there's new logic stopping it from over-assigning patrols to naval invasion support. If you've ever watched the AI park its entire fleet on pointless patrol duty while an invasion goes unsupported, this should help. On the performance side, a fix targeting large-scale naval battles with 1,000-plus ships is in, which is the sort of thing that makes late-game multiplayer sessions actually playable rather than a slideshow.
Bugfixes cover the USA's inability to build 1940 CVs, strike forces getting stuck on invalid targets, incorrect snow modifier values, and a crash tied to carrier airplane deployment. Lend lease also defaults to max amounts now, which is a small but sensible quality-of-life change. Everything in the update is listed below.
Full Patch Notes
▲ Buff▼ Nerf✓ Fix◆ TweakGenerals!
Before we head out on our 4-Day LOA we wanted to give you another OB update. Give it a try, leave us a lot of feedback here, and we'll be back soon to take it all in and make potential adjustments.
How to join this Open Beta:
This beta client is Case Green v1.18.1.0.9197 (01c8)
To install Open Beta client, follow the instruction below:
- 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
If you are already on the Open Beta client, you should get an update automatically.
Finally, to report any issues you find, in relation to this beta, please use the bug report forum and make sure to include the version you’re using. That way our Jira won’t go nuts trying to figure out what bug report belongs to what.
Open Beta Update V Notes
Gameplay
- Made lend lease default to max amount for 'once' and to 100% for 'percentage' modes
- Updated supply tooltip to show more careful where all supply is coming from
Stability & Performance
- Fixed performance in very large scale naval battles (1000+ ships)
- Fixed a dx11 rendering bug
AI
- Fixed a bug where England could not build improved battleships
- Extensive rework of italian naval equipment
- The AI will now train their troops more often
- Updated generic taskforces so they are a bit more sensible
- The AI will try to train their ships a bit more opportunistic
- The AI will be a bit more sensical with picking a homebase for its standby fleet
- Added logic to prevent the AI from assigning too many patrols to support naval invasion
Modding
- AI objectives will respect blocked naval regions now and not consider them for naval mission assignment anymore
Bugfixes
- Fixed a bug where ships were partially considered for supply need
- Fixed a bug where USA was unable to build 1940 CVs
- Fixed a bug where a strike force sometimes gets stuck on an invalid target and stops working
- Fixed a bug where wrong snow modifier values were shown + fixed a bug where the leader snow adjuster didnt work as intended
- Snow attack penalty is now shown on the move-arrow tooltip
- Removed legacy plane techs from BBA-enabled starts for 36 minor nations
- RI Bolzano in the 1939 OOB now uses the correct ship_hull_cruiser_2 (Bolzano Class)
- Convoy raiders won't join or reinforce a combat unless there are enemy convoy's to shoot at
- Fixed a crash related to carrier airplanes being deployed
As you were!
(And try to leave this place in one piece while we're out!)
Stay on top of every update — find all the latest patch notes and gaming news at XP Gained. Join our Discord for live patch note alerts and discussion.
Written by
Nathan LeesGaming journalist and founder of XP Gained. Covering patch notes, breaking news, and updates across 160+ games.
Related Posts
Hearts of Iron IV HOI IV | Open Beta Update VI Notes (22nd May 2026)
The final planned open beta update before HOI IV's Anniversary Patch lands on June 6th, bringing naval AI improvements, Nationalist China rebalancing, and a stack of bugfixes.
Hearts of Iron IV | Patch 1.18.2 Notes (20th May 2026)
Paradox ships what it's calling the last planned patch focused on Peace For Our Time, with Czechoslovakia balance overhauls and two crash fixes leading the way.
Hearts of Iron IV Dev Diary - OPEN BETA UPDATE IV Notes (8th May 2026)
Open Beta Update IV lands with a major naval AI overhaul, submarine rebalancing, and a preview of what's coming in the anniversary patch.