In this update15
Full notes
Full Cepheus Protocol update
Read the full published notes in a cleaner layout. The original post stays linked below.
What changed
- Server
- Compatibility
- Performance
- Gameplay
- UI and audio
- Maps
Cepheus Protocol changes
TLDR
The Rebuild is now the standard installed version of Cepheus Protocol.
The old version is now called Legacy, and it remains available as a Beta option.
This rebuild was done to restore stability, improve performance, and modernize the foundation so the game can scale again.
That same foundation also allows co-op to exist from the start, instead of being bolted on later.
We are targeting end of Q1 2026 to bring back the remaining missing pillars, rebuilt and improved.
Which Build Should You Play?
Default (Standard Install) This is now the rebuilt version of Cepheus Protocol and the main version we maintain going forward. Play this for the current supported game, best performance, and all new updates.
Experimental (Beta Branch) This is the testing branch ahead of Default, where upcoming features land first. Expect bugs, frequent updates, and possible save issues. Opt-in only if you want to help test new changes early.
Legacy (Original) (Beta Branch) This is the preserved prebuild version for older saves and the original gameplay foundation. Opt into this if you want to continue old saves or stay on the classic build. This branch will not receive future updates. You can see the "foundation" that we based the rebuild on for the newly merged into "default" here.
Legacy (Pre Merge) (Beta Branch) This is the last version from before the rebuild became Default. If you were playing the rebuild while it was still a Beta branch.
The Big Change
Going forward, when you install Cepheus Protocol, you are installing the rebuilt version.
For most of the last year, the rebuilt version existed as an opt in Beta branch while we validated the foundation in public tests. A lot of players never saw that Beta branch, which caused real confusion about what version was being worked on and why certain things felt inconsistent.
So we are ending that confusion. The game is alive as ever and is still passionately worked on a daily basis by our team. We have been biding our time developing the rebuild on public/private betas slowly ticking away at the core mechanics missed from the rebuild readding them as we go. We now feel the current state of the game is enough to flip the builds.
Going into next week we will be shipping Doctrines and start the save system. We expect to have an early doctrines to show by Friday and have it in UI wise by mid next week. We will update as we progress here and on our discord.
A quick Catch up!
[dynamiclink href="https://steamcommunity.com/games/979640/announcements/detail/537736957039477253"][dynamiclink href="https://steamcommunity.com/games/979640/announcements/detail/537735054151909378"]A few notable changes recently:
Infected Military, Police and Swat will now roam the island with higher stats then standard infected. They start showing up early and increase in numbers as the days go on!
Steam post imageSteam post imageSteam post image
Infantry Gates
Steam post imageSteam post imageNew Infected Variants replace legacy models
[dynamiclink href="https://youtu.be/FlKfVGDYkPM"]
16 Player Coop RTS/TPS hybrid gameplay!
Firing Computer from the MLRS ported to the Cerberus Mortar with the rebuild
[dynamiclink href="https://youtu.be/BzcmJ-hsIeI"]
Legacy Version
Legacy remains available as a preserved snapshot of the pre rebuild version.
If you want to keep playing that older snapshot, or if you want to keep older saves, you can do that through Steam Betas.
What This Rebuild Actually Was
This was not a content patch. It was a full foundation revamp.
We rebuilt the core systems so the game can scale properly again, run better, and stop breaking under the weight of legacy technical debt. That benefits everything:
Single player flow and stability
AI behavior and consistency
Vehicle systems and reliability
Large scale performance
Future content velocity
Co-op support as a first class feature
Co-op is not the point of the rebuild. Co-op is one of the benefits of doing the rebuild correctly.
What You Can Play Right Now
Horde Mode
We currently have two Horde experiences built in the rebuilt framework:
Half Moon Bay (Horde Rush)
Forward progression style Horde
Push the map and keep momentum instead of only holding ground
RTS Coop Test (Horde)
Traditional horde map experience
Operators (Foundation Now, Expansion Later)
Operators were built in lockstep with the rebuilt foundation, not as a disconnected system.
Current Operator baseline includes:
Weapon customization (early version)
Attribute points
Appearance baseline
Gunsmith/Operator UI is not final and will be improvement over the next few weeks as Winters mockups up a new design
True RTS/TPS Hero Units you can customize
Operators will expand significantly as we move into Doctrines, including:
Driving vehicles
Operating turrets
Using new and ported abilities such as laser designation for support actions when we add in the ability to call in airstrikes and support options!
Pandemic Mode Progress
Pandemic is now the next major phase, built on the foundation validated through Horde.
Currently playable areas include:
Calypso
Half Moon Bay
Treasure Island Open World Slice
Additional areas planned but currently locked:
Angel Island
San Francisco North
These areas will unlock later once missing enemy roster and mode pillars are complete.
What Still Needs To Be Finished
Here is the consolidated list, in one place, so there is no confusion.
Missing Or In Progress Systems
January Goals
Remaining Vehicle Abilities And Behaviors
Bradley TOW
Merlin vehicle transport
Doctrines
Save System for Pandemic
BUGS, BUGS and Bugs! We still are hunting down desyncs and bugs as they are reported!
Game Balance - Is still ongoing and being tweaked. Michael is monitoring Steam/Discord for feedback
February Goals
Any Remaining Bugs/Performance Tweaks/QOL Adjustments based on community feedback
Remaining Enemy Roster Needed For Angel to be unlocked
Leviathan
Birds
Additional Pandemic Regions Locked Until The Above Is Complete
Angel Island
San Francisco North
TBD
We are committed to not rushing to the "end" to ensure everything prior is working correctly. These are the ones currently in limbo that we will be tackling once the above list is "completely" done.
LHA6 & LCAC
Civilian Evacuation
Dynamic Civilian Groups
That is the remaining gap we are closing through Q1. Anything else will be discussed only after the current list above is done.
Q1 2026 Target
Our target through Q1 2026 is to bring back the remaining missing pillars and have the rebuilt version fully represent the complete Cepheus Protocol experience again, but better.
That means:
More stability and performance
Larger scale gameplay
More and better maps
Complete Pandemic mode pillars
Operators expanding toward Doctrines
Final Notes
This build switch is about clarity.
From now on:
The installed version of the game is the rebuilt version
Legacy remains available as a preserved snapshot
The rebuild is what we maintain and grow from here
If you want to help shape it, the biggest thing you can do is:
Play the current build
Give feedback on what feels good and what feels broken
Report bugs and edge cases
Thank you for sticking with us through this rebuild period. The foundation is finally where it needs to be, and now we are building the rest of Cepheus Protocol on top of it.
Source
Changelog.gg summarizes and formats this update. How we read updates.
