Xcode 12 StoreKit testing for existing iOS 13 apps?

I've watched the session on the new StoreKit testing that Xcode 12 brings, and it looks great. I'm currently working on an app that targets iOS 13, which I haven't yet released, and I need to implement in-app purchases. Does anyone know if it's possible to make the new StoreKit testing work for an app I intend to release this summer, on iOS 13, or will I have to do things the old way until Xcode 12 is formally released and App Store Connect is ready for it?

Thanks =)
StoreKit Testing in Xcode 12 supports iOS 14, tvOS14, watchOS 7, and macOS Big Sur apps.
Xcode 12 StoreKit testing for existing iOS 13 apps?
 
 
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