• Fixed an issue causing no sound output in games that open and close audio devices quickly like Super Blood Hockey
• Stability and security improvements

This combines updates .18 and .19 from the beta channel. Valve is usually more specific about what “stability and security” fixes include. Between being oddly non+specific and the fact that they pushed this update out as quickly as they did, I have a suspicion they were fixing a significant security issue. So probably best to update as soon as you’re able.

The sound fix will be nice for affected games as well. I know Dishonored 2 would lose audio after the deck went to sleep, and that’s fixed now. I can’t confirm if it was actually this patch that fixed it though, but it’s a great fix to have regardless.

Here’s the official patch notes