Updates to Team Fortress 2, Day of Defeat: Source and Half-Life 2: Deathmatch have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:
Source Engine Changes (TF2, DoD:S, HL2:DM)

• Added a new ConVar sb_filter_incompatible_versions. This will default to true and hide servers on the Internet tab that are running incompatible versions.