Dedicated Server Steam Workshop Issue (2025)

Currently, there is a problem with updating new workshop items on the KF2 server side. More specifically, all mods (maps, packs, and mutators) that have been compiled/created since 11 July 2025 will no longer be updated on the server. This behavior is not observed on the client side.

• Around February 2025 or before, Steam has added support for ZSTD compression, a faster and more efficient compression algorithm, to improve game download speeds. This new compression method will be used for downloading game files, replacing the previous LZMA compression for certain data chunks.
  
  
• The latest Steam DLLs from SteamCMD appear to be version 9.86.62.31 from 27 June 2025, and are confirmed working with new workshop items (presumably supporting those new ZSTD compressed chunks).
  
  
• On 11 July 2025, Steam workshop presumably started saving new content as ZSTD compressed chunks.
  
  
• Killing Floor 2 dedicated server ships old Steam DLLs, which appear too old to support the new chunks format, and so started failing when downloading them.

TWI needs to make a new dedicated server release with updated Steam DLLs. But we don't know when that will happen. Therefore, I am providing a temporary solution to this problem.

• Launch SteamCMD to get the latest updates.
  
  
• Copy the following DLL files from the SteamCMD directory, which are required for updating the server side:
  
  • steamclient.dll
    
  • steamclient64.dll
    
  • tier0_s.dll
    
  • tier0_s64.dll
    
  • vstdlib_s.dll
    
  • vstdlib_s64.dll
  
  
• Place the copied DLL files in the Binaries\Win64 directory of your server and confirm the replacement.

I am not currently using Linux and cannot find a solution for this platform on my own. But you can use the following solution if it helps:

• Launch SteamCMD to get the latest updates.
  
  
• Copy the following SO files from the linux32 and linux64 of SteamCMD directory, which are required for updating the server side:
  
  • crashhandler.so (linux32 dir)
    
  • libtier0_s.so (linux32 dir)
    
  • steamclient.so (linux64 dir)
  
  
• Place the copied SO files in the Binaries\Win64\lib64 directory of your server. Beforehand, you can rename the old files to so.old if you need them.