sp-tarkov/build 4.0.0

SPT 4.0.0 (40087)

on GitHub

Requires EFT 0.16.9-40087 (released 12th September 2025)

You will NEED the .NET 9 runtimes:

• https://dotnet.microsoft.com/en-us/download/dotnet/thank-you/runtime-9.0.9-windows-x64-installer
• https://dotnet.microsoft.com/en-us/download/dotnet/thank-you/runtime-aspnetcore-9.0.9-windows-x64-installer

Release notes

• Internally, this is the biggest release we have ever made. We swapped from using Node.js to .NET and from TypeScript to C#. We went over all 150,000+ lines of code by hand. No vibe coding here.

  • Stability - less bugs
  • Performance - We can do proper multithreading and use more than 1 core (in the server, not client)
  • Familiarity - Majority of the contributors have professional experience with C# and the .NET ecosystem

• At first the goal was to do a 1 to 1 port of the 3.11.3 server. We soon realised it would cause a larger disruption to modders who would need to rewrite their mods possibly multiple times as we refactored the server after release. Instead we we went over all 150,000 lines AGAIN and rewrote them to make as much use of C# and .NET as we could.

• We wanted to target a version of EFT that was released prior to EFT 1.0. This is because we suspect 1.0 will take a long time to emulate in SPT. rather than waiting another year for SPT, we wanted to get it out now with all the improvements BSG have added since 3.11.3 came out.

• One huge benefit of going over the code was we had to fully understand what every line was doing. This had the benefit of letting us find and fix a LOT of bugs, probably over a 100. It's hard to estimate because no one wrote down what was fixed as we were porting the codebase.

• We were hoping to target .Net 10 as it has a lot of excellent performance improvements but Microsoft have not released it in time for SPT 4.0, We will look into .NET 10 for SPT 5.0.

• There have been so many people contrubuting to 4.0, they're listed below and on a secret webpage hidden inside the server. Good luck finding it!

Automatic install instructions

This is the recommended way to install SPT
https://forge.sp-tarkov.com/installer

Mod compatibility

• Incompatible with ALL mods not made for 4.0.0

Profile compatibility

• Incompatible with 3.11.0 profiles and older
• 3.11.3 and 3.11.4 profiles with no custom items/traders/total conversions should work

Manual install instructions (Optional)

https://github.com/sp-tarkov/build/wiki/Manual-Install-Instructions

Upgrading from 3.11.x

• Not possible due to the change in client version. A fresh install is required

Changes

EFT Changes summary:

• Hideout crafting QoL changes
• Ai behaviour and spawn improvements
• More hideout posters
• Rocket launcher + unlock questline
• Slightly lower in-raid memory usage
• Shadow improvements
• Audio rework
• Ref quest rework
• Added Ak-50 weapon + quest line to unlock
• Prestige level 3 and 4

ADDED

• Added active boss system, each week a map picked randomly gets its boss chance changed to 100% and a skull appears above it on the map screen
• Added gift codes: ROADMAP, RELEASEISCOMING NOESCAPE, DEVELOPERSDEVELOPERSDEVELOPERS
• Added support for migrating 3.11 profiles to 4.0.0
• Added system to prevent alt+f4 exploiting to save gear on death, disabled by default
• New flea market pricing system - prices are based on handbook data instead of live pvp snapshot
  • Editable via config
• New weather generation system
  • Attempts to make weather more variable
• Custom PMC spawn system
  • Attempts to keep raid active by spawning PMCs at start and throughout raid
• Added support for modders to utilise Blazor, MVC and MudBlazor
  • Create custom web pages on server

MODIFIED

• Server rewritten, now a .NET 9 Kestrel server using C#
• Refactored and tuned repeatable quest system to behave more like live
• Adjusted Partisan magazine+grenade count to better match live
• Updated PMCs to use new gear added in EFT 0.16 patches
• Regenerated bot loot and equipment using only new data from EFT 0.16
• Regenerated map loot using only new data from EFT 0.16
• Regenerated trader assort data
• Added a fix for BSG forgetting to include the new dogtag IDs in the dogtag case whitelist
• Reduced zombie head hp to 10 from 60
  • This differs from live but its almost required to make the Halloween even remotely fun, they're walking tanks otherwise

FIXED

• There have been SO many bugs fixed (100s) it would take forever to go through the commits and write them down
• Fixed raid time not matching live when playing in a timezone other than +0

MODDERS

• Custom DI system, based on the best bits of Java Spring
• Added custom quest insertion system via CustomQuestService
• Replaced load order system with improved, highly granular version
• All routes use full async/await
• Nearly all MongoID-holding properties are strongly-typed using a custom class instead of string
• Added loot.json/staticItemWeightAdjustment to allow modification of loot item weights in containers
• Rewrote all example mods in C#
• Added dictionary called CustomFlags to each profile template for storage of flags on custom profiles

Known SPT issues

https://github.com/sp-tarkov/build/wiki/Known-SPT-issues

Known NON-SPT issues

https://github.com/sp-tarkov/build/wiki/Known-non-SPT-issues

Direct Download

https://spt-releases.modd.in/SPT-4.0.0-40087-0582f8d.7z

Thanks

DrakiaXYZ
Lacyway
Refringe
ArchangelWTF
CWX
CJ-SPT
hulkhan22
cp89gamedev
clodanSPT
VforValens
KaenoDev
R3ality
tetrisdev
RuKira
GrooveypenguinX
XeonDead
qingchunnh
BlueXTX
qe201020335
angel-git
Everyone in #be-testing who gave up their free time to find and report issues