Symbols folder missing from App Store build IPA- exists in archive- Xcode 10.1

While archiving my app for an App Store release using Xcode 10.1 (source is in Swift 4.0)- I see that my unzipped .ipa file does not contain the usual Payload, SwiftSupport and Symbols directories. Instead it just has the Payload directory. When I compiled using Xcode 10.0, it did have all these directories. I need to have the Symbol files so that I can symbolicate crash logs received from Crashlytics. Tried out a few options but in vain. Anyone with ideas? Did something change in Xcode 10.1? I read the following- A thinned .ipa is a compressed app bundle that contains only the resources needed to run the app on a specific device. Bitcode has been recompiled, and additional resources needed by the App Store, such as .dSYM files and On Demand Resources, are removed. For App Store apps, this .ipa is downloaded to devices running iOS 9 or later. ((https://developer.apple.com/library/archive/qa/qa1795/_index.html) and also Build System Resolved Issues The new build system supports On Demand Resources (ODR). (31508570)from Xcode 10.1 release note. However, I am not entirely convinced these changes relate to my issue.