Through 1.5.6 Studio would “freeze” or crash after awhile, perhaps a half hour, streaming via UPnP. (Direct connection has not given any problems.) With 1.5.7, playback via UPnP has continued just fine for quite a while. I intentionally left Studio on with the music stopped and set to UPnP for an hour or so between listening sessions, just as a further test, and afterward when I selected music with the remote and pressed Play, playback began again without incident.
The computer running Audirvana is in a different room from my main stereo system. There are various ways to send an audio signal from a computer over Wi-Fi to an audio system. The one Audirvana uses is probably the most common one, a standardized format called UPnP/DLNA, which stands for Universal Plug ‘n’ Play/Digital Living Network Alliance. (There is a variant of this format used by some audio companies called OpenHome, which Audirvana also works with.)
So what I was saying in my original post is that with previous versions Audirvana had a tendency to become unresponsive after a while if I was using it to transmit audio wirelessly to my main system, though if I used it with a DAC directly connected by USB to the computer running Audirvana there was no problem. With 1.5.7, both wireless and direct connection are working well.