Hi there --
At this point, the current version of Go Button (3.3.7) still supports only two-channel output, even when connected to an external interface. We have long-term plans to add support for multi-channel output, but we don't have a timeline yet for when this will happen. In the meantime, you'll need to use a different app to get 4 channels of audio output.
If you are not familiar yet with our flagship Mac app QLab, please check it out at
https://qlab.app. You can download the free version to try it out. There is a 60-minute Demo Mode that lets you try out advanced features too. And you can rent an Audio license that unlocks support for 128 channels of audio output for just $5 per day.
Also, QLab can import your Go Button show files to help get you started quickly.
Brent