we use xcrun xcodebuild  in sh file to run builds on bamboo machines. recieving the error that swift packages are not supported in legacy build. How to use new build system using xcrun xcodebuild command

I'm using a solution based on this :  https://stackoverflow.com/questions/26081543/how-to-tell-at-runtime-whether-an-ios-app-is-running-through-a-testflight-beta-i TLDR, checking if Bundle.main.appStoreReceiptURL?.lastPathComponent == "sandboxReceipt"  But this solution is returning true for isTestFlight even when I build the app in Debug.

I want to enable a certain feature for some of my Internal and external users in the Test Flight using my application. Is there a way I can fetch his details or id programatically in my code and turn the feature on for those users?