Stellaris Dev Diary #409 - The 4.3 ‘Cetus’ Open Beta Continues

by Eldarin

Hello everyone! Welcome back to Stellaris Dev Diaries!

During the Cetus cycle, dev diaries will be on a once-every-two-week cadence.

The 4.3 ‘Cetus’ Open Beta continues!

The State of the Open Beta​

Last week we casually snuck the ability for multiplayer games to allow new hotjoins while an existing hotjoin was ongoing into the Beta, but a flag wasn’t being set properly and broke Resync, so we’re updating again this week.

4.3 ‘Cetus’ Open Beta Patch Notes 2026-01-22

Improvement​

• Field Modulation, Eco Simulation, and Geothermal Fracking technologies are now marked as Gateway technologies for Rural District Specialization.
• Improvement "Scorched World Heralds" civics now mention that diplomacy with other Thermophiles is possible
• Option text for Rogue Servitors discovering alien life is tonally appropriate
• First Robot timeline event blocked for machine species

Balance​

• "Scorched World Heralds" cannot longer grant Full Citizenship or Residence status to conquered non-Thermophile pops
• Reduced the minimum fleet power necessary to trigger the fight with the ambushing Cutholoid to 600. It'll be a tough fight and you'll probably lose some ships, but usually win.

Bugfix​

• Fixed the Resync button in multiplayer
• Fixed some scoping issues with the random events if you neighbour the caravaneers
• The Luminary for Under One Rule will now have the correct number of traits for their level
• Fixed the Galactic Crucible not triggering a notification / event choice after capture in certain situations (after the war)
• The "Scion" origin now blocks the "Scorched World Heralds" civic
• Modifiers from starbase targeting owner country now makes the country recalculate as it should
• Upgrading a Starbase with a Resource Silo on it no longer lowers the total resource capacity for the Empire.

Performance​

• Optimized event parameter storage.
  Effects of this include:[list]
• Reduces heap allocations for 95% of EventScope uses.
• AddOrUpdateScopeParameter now 71x faster. Improved consistency and eliminated performance spikes.
• CreateEventScope now 48x faster. Performance variability eliminated.
• AddScopeParameter 83x faster. Highly consistent.
• GetScopeParameter 35% faster - median time reduced by 84%; meaningful improvement on a less frequent code path.
• Ship CalculateModifier 68% faster.
• Army CalculateModifier 5.3% faster.
• Uninhabited Planet DailyUpdate 3-5% faster.

Summary: Changes result in smoother gameplay, reduced load on memory allocator, frame processing time reduced by ~10%.​

Note: This change snuck into last week’s update.​

• Improved Scripted Trigger caching
• Optimize string allocation 76% faster

Let’s look at some of the feedback that we’ve gotten over the holidays.

Just over half of the respondents placed the economic balance rating as “just right”, with the remainder being split over a nice curve in both directions, skewing a little bit towards being a bit underpowered.

Several of you mentioned Tankbound in comments - we agree that they’ll need more review. Others commented on Energy being more of a struggle, which is a significant change from earlier 4.x builds, with some comments stating a dislike of the “static job” buildings and how they don’t fit terribly well in the current design.

While there’s a nice spike at 3 for mechanical ships, there’s a pretty strong lean towards “too weak” for Fauna. Most comments in general were extremely in favor of the changes, though pirates and Fallen Empires were mentioned repeatedly, as well as that first Cutholoid special project. We’ve already nerfed pirates, and we do want Fallen Empires to be much more of a challenge than they’ve been for a few years, but they might be overdoing it a little. The Cutholoid definitely wasn’t fun - so we’ve reduced the required threshold to challenge it in today’s update.

Food production appears to be considered an issue with Space Fauna empires.

Many of you wrote that static defenses were too powerful - though we did adjust some of them in last week’s beta update. We’ll continue monitoring them.

Battlefield control weapons from Bio-Ships may be a bit oppressive with the lower ship counts.

The general consensus seems to be that high Stability is still too easy to maintain in the Open Beta, and many of you were pretty content with the changes to Empire Size.

Overall, the feedback thus far has been solid enough that I expect that we’re on track to go through with both the economic rebalancing and the naval changes, and will continue balancing with the expectation that both will ship with 4.3 Cetus.

The Stellaris Bug Report Forum​

We have an update to the bug report forum from @MrFreake_PDX :

In response to your feedback about the level of transparency around Stellaris Bug Reports, we’ve been trying to improve in that area over the last couple of months. Some of you may have noticed myself and others replying to bug reports more often, keeping you apprised of the status of the bug reports. In order to be able to turn on further automation with regards to this, we needed to switch to a new bug report forum style. This is still a work in progress, and we hope to see the new features roll out fairly soon.

All previously reported bugs are still logged internally, so don’t worry if you can’t see a bug you’ve reported in the past. We will continue to go through them, but any new bug reports should be added to this new section on the forum instead.

In order to do this, we’ve had to change the format of our Bug Reports forum to line up with the fields we used in our internal bug tracker.

Please fill out all of these fields to the best of your ability.

How to Verify your Game Files:

On Steam:

Right Click Stellaris (in Steam), go to Properties, Local Files, and click Verify Game Files

On GOG:

Right click your game in your library, Click Manage, Click Files at the top, Click Verify and Repair and let it finish

On Microsoft Store:

Select your game in your library, Click the Customization button (to the right of the Play button), Click Manage Installation, Click Verify/Repair and let it finish

How to Verify your Mods are disabled:

All versions:

Open Stellaris, at the Main Screen at the bottom, mouse over the version number, if it says “Checksum Is Modified” then you still have a mod enabled (or have extra/modified versions of files in your Stellaris directory).

How to use the new Bug Report form:

Here is the new bug report form, these have been changed to better line up with the fields in our internal bug tracker.

Issue Type:

Don’t worry too much about getting the correct Issue Type, QA can update the report to ensure it has the correct issue type.

• VFX - Issues with Visual Effects (Explosions, Space Storms, etc)
• Audio - Issues with in-game sounds or music
• Out of Sync - Report multiplayer desyncs. Please include OOS reports from the host and client. You can find OOS reports here:[list]
• On Windows: C:/users/YOURUSERNAME/Documents/Paradox Interactive/Stellaris/OOS/
• On Mac:[olist]
• Open Finder: Click the Finder icon in your Dock.
• Go to Documents: Click on Documents in the sidebar.
• Navigate: Open the Paradox Interactive folder, then Stellaris, then the oos folder.
• Find Files: Inside OOS, you'll see folders for each desync. We need one from the client who desynced, and one from the host of the multiplayer game

On Linux:

• if environment variable XDG_DATA_HOME is not empty logs will be in:

$XDG_DATA_HOME/Paradox Interactive/Stellaris
Otherwise they will be in:
~/.local/share/Paradox Interactive/Stellaris

• Content Design - for literally unplayable typos, issues with Script, in-game Events, Situations, etc.
• Crash - For crashing issues, please be sure to include a Crash Report. By default you can find Crash Reports here:[list]
• On Windows: C:/users/YOURUSERNAME/Documents/Paradox Interactive/Stellaris/Crashes
• On Mac:[olist]
• Open Finder: Click the Finder icon in your Dock.
• Go to Documents: Click on Documents in the sidebar.
• Navigate: Open the Paradox Interactive folder, then Stellaris, then the crashes folder.
• Find Files: Inside crashes, you'll see folders for each crash, containing exception.txt, error.log, debug.log, and settings files, which are very helpful for debugging.

On Linux:

• if environment variable XDG_DATA_HOME is not empty logs will be in:

$XDG_DATA_HOME/Paradox Interactive/Stellaris, otherwise they will be in: ~/.local/share/Paradox Interactive/Stellaris

UX - Report issues with the User Interface

Code - for issues that are not handled through script. Don’t worry too much about having to choose between this and Content Design, QA can update the report

Game Design - for systems-related issues, whether they be mechanics that don't seem to work right, the numbers seeming off on something, or general balance issues. If it fits on a spreadsheet, it probably goes here

Art - Issues with models, event art, etc

Summary:

• This will be the title of your bug report, keep it short and succinct

Description:

• Here you can describe the issue in more detail

Expected Result:

• What you expected the outcome to be when you encountered this issue

Actual Result:

• What actually happened when you encountered this issue

Steps to Reproduce:

• We always treat this internally as an “Explain Like I’m Five” steps to reproduce, so include things like “Launch the Game”, “Start a New Game”, etc.

Repro Rate:
This is the Reproduction Rate. Does it happen every time, or only occasionally? This field can let QA know that if they don’t reproduce the issue the first time, that they should probably try, try again.

Attachment:
Use this to upload screenshots, save files, and in the case of Crashes or OOSes the applicable reports (see the sections above)

We would like to thank you all for your cooperation while we roll out this new system, and hopefully give you all a little more transparency into what’s going on behind the scenes here at Paradox Green!

What’s Next?​

The next Stellaris dev diary will be about further updates to the Open Beta, and will be on February 5th.

See you in the beta!

How to Opt-In to the Open Beta

To access the Stellaris beta, go to your Steam Library, right-click the game, and select "Properties". From there, choose the "Betas" tab, and in the "Beta Participation" dropdown menu, select the "cetus_open_beta" beta branch from the list.

A Note for Linux Users:

The Linux binary at the moment requires a openssl 4 enabled version of curl, this is not provided by Steams base environment, we are currently addressing this.
You can either try and run Stellaris directly if your system has this provided for you or use proton to run the windows version

Run Stellaris directly:

• Right click Stellaris in Steam and select "Properties..."
• Goto "Installed Files" tab and select "Browse..." (this should take you to where Stellaris is installed)
• Find the file "stellaris" and double click it

Run thru Proton:

• Right click Stellaris in Steam and select "Properties..."
• Go to "Compatibility" tab and tick the "Force the use of a specific Steam Play compatibility tool" checkbox
• Select "Proton 10.0-3" or a suitable version (https://www.protondb.com/app/281990 for help)
• Update the game and press "Play" in steam