SteamDB has spotted an update for the game:
Size is ~10 MB (with Workshop Tools installed). Although somewhat unlikely, more info will be edited in if it does become available.
This update has some
under-the-hood work around the game's sound system , specifically, a change to the "soundinfo" console command's output- This is to assist with triaging
a few trouble reports of no sound following last night's update (which discontinued the XAudio library in favor of SDL) - If you are experiencing no audio following last night's update,
please see instructions from Jeff Hill here to help him triage - In a nutshell:
old output (from several updates before, when XAudio was still around) vsnew output
- This is to assist with triaging
Source: https://www.reddit.com/r/DotA2/comments/qvo7m9/dota_2_update_for_111621_111721_utc/