All the issues are linked to Source engine and client
Video game developer Valve is updating Team Fortress 2, Day of Defeat: Source and Half-Life 2: Deathmatch in order to eliminate a crash linked to an older version of Direct X and a problem with the game client.All the changes are automatically applied when a player launches the Steam digital distribution service.
The entre list of changes reads:
Source Engine Changes (TF2, DoD:S, HL2:DM) - Fixed a client crash related to DirectX8
Team Fortress 2Fixed a client crash related to the main menu
Valve adds that a number of smaller issues have also been addressed although they are not listed in the official change log.
Team Fortress 2, Day of Defeat: Source and Half-Life 2: Deathmatch are still very popular with Valve fans and their communities regularly flag issues that the company then fixes.