Source SDK Release Notes

Note:The latest release note on Steam News page is no longer updated. This page is currently up to date as of March 2025.

Note:If you see this page when you first open the "Source SDK" (AppID 211) launcher, please note that the standalone Source SDK tool/launcher are no longer updated, and does not support Source 2013 games. The deprecated Source SDK tools are provided to create content-based mods for Source 2009 or earlier, and to obtain source code & create mods for Source SDK Base 2006 and Source SDK Base 2007.

To launch the SDK applications (Hammer, HLMV, etc...) manually on Source 2013 games, see SDK Installation - SteamPipe migration section.

= Multiplayer (Team Fortress 2 branch)

• Updated SDK code (sync with latest TF2 version).
• Remove MFC dependency in the launcher exe (afxres.h > winres.h)
• Add prediction for thermal thruster + self-stun
• Fix crash with game_round_win in koth
• Move .357 snap after firing to client-side
• Remove temporary player jingle files if tf_delete_temp_files is enabled

= Multiplayer (Team Fortress 2 branch)

• Fix prediction for jumping when huntsman is charged/released
• Fix middle mouse kicking you in Passtime
• Fix PLAYER_FLAG_BITS truncating m_fFlags sent to clients

Source SDK 2013 update (2/26/2025)

Multiplayer (Team Fortress 2 branch)

• Add convar to control max MvM robots
• Fix radial fog not being enabled in 3D sky on official maps

Source SDK 2013 update (2/18/2025)

An update to Source SDK 2013 has been released. The major changes include:

Singleplayer (Source 2013 Singleplayer)

• GitHub branch moved from sp folder to singleplayer branch. Code remains unchanged.

Multiplayer (Team Fortress 2 branch)

Note:Info copy-pasted from Counter-Strike: Source Feb 18, 2025 update notes, and edited to only mention fixes that applies to all updated games ( to , like , ), and SDK 2013 MP. Game-specific fixes are not included here.

• Added 64-bit Support. 64-bit binaries will automatically be launched on systems with a 64-bit OS.
• Added a borderless window option to video settings
• Added bicubic lightmaps (from Half-Life 2: 20th Anniversary Update)
• Added radial fog (from Half-Life 2: 20th Anniversary Update)
• Added support for Steam Networking
• Added UI scaling for high-resolution screens
• All remaining Valve games running on Source 2013 Multiplayer (, , and SDK) have been upgraded to Team Fortress 2 branch.
• Made the default server name for listen servers include the player's name
• Made the game launch in native resolution by default instead of 640x480
• Client-side prediction fixes (these fix 'jank'/rollback in certain situations)
  • Fixed a prediction bug where if the player was moved on the client, their input-based movement for that tick was not taken into account in non-player actions
  • Improved prediction for walking on props and other entities
  • Made certain client-side entities only trigger local prediction errors
    • e.g. If the viewmodel experiences a prediction error, the player will not experience a prediction error
  • Fixed prediction of viewmodel sway
  • Fixed a prediction error regarding weapon idle animations
• Fixed certain breakable props not gibbing correctly
• Fixed an issue where certain variables like position would not be updated correctly to match the server in certain situations
• Fixed the player's base velocity (eg. conveyors, moving items etc.) getting subtly out of sync from client/server
• GitHub branch moved from mp folder to default (master) branch. Code remains unchanged.

Updated source code (3/9/2025)

• Source 2013 Singleplayer: Source SDK 2013 GitHub repo.
  • Note:SP code remains unchanged since 2014.
• TF2 branch (newer Source 2013 MP): Source SDK 2013 GitHub repo.

Previous releases

• See the Source SDK release notes archive for information on previous releases.