Via CS:GO Blog:

MISC

• Fixed stability issue for physics collision detection against displacement surfaces.
• Fixed some situations in which stickers would not appear properly on weapons in-game.
• Fixed an issue where MP3’s embedded in maps wouldn’t work. (Thanks to Steam user MajesticCatDog for help in diagnosing this issue).
• Removed legacy audio cache commands.

SDK

• When loading the map in development mode with “developer 1” enabled, engine will display DISP_VPHYSICS warnings for displacements with degenerate collision faces. When such displacement faces are encountered, the entire displacement object will have no collision in-game. Additional clip brushes or adjustments to such displacements may be added by map authors in these cases.