Since build 2.6.10 iOS SDK is shipped with WebRTC framework patched to prevent microphone permissions request while playing WebRTC stream on iOS 14.

WebRTC framework is nested which may lead to AppStore publishing issues. To workaround this, move WebRTC framework to the same level as FPWCSApi2.framework or FPWCSApi2Swift.framework

mv ./FPWCSApi2.framework/Frameworks/WebRTC.framework ./
rmdir ./FPWCSApi2.framework/Frameworks

See details about using frameworks in application here