For Singapore company, I leave 8, 10, 14 (#2 and #3 checkboxes) and 15 empty. I gave 9b. and ticked 14 #1.

You might want to check this. https://stackoverflow.com/a/62840934/772481 The answer appears to be that the AVAudioSession.Mode is automatically setting some options under the hood. Apple seems to have made the design decision that the .voiceChat mode should always duck others for the best experience. This is similarly true in the .videoChat mode, both of which are the obvious modes to use with an Agora call. Using those modes seems to automatically set the .duckOthers flag. I was able to solve this issue by setting the mode to .videoRecording, which is designed for apps that are recording audio and video, and therefore doesn't automatically set .duckOthers. Because this isn't actually what you're doing, it's definitely a workaround, and might have other side effects.