did you ever get this working?

looked like this is fixed now!

We're having the same problem on testflight sandbox. As a result, we cannot test any subscriptions. We get a lot more data than the people above in the signedRenewalInfo field, but cannot decode it.

This is a good example of how to add a sink stream: https://github.com/MarkBesseyAT/CameraTest/tree/b7c2923b209ad567c55d35bff959fa2b514c341b

Having the same problem. Did you end up solving it?