Apple broke us on old phones

As written up in more detail in this article we just published:
https://medium.com/touchgram/blindsided-by-bitcode-2adca2993ecf?source=friends_link&sk=57bf3ffc6478e3f323c914d320ffc08d

Apple's processing of apps on the store, which optimises what they download to your specific phone type, broke all apps using the new Concurrency features. The bug hits anything deployed on iOS versions earlier than the current iOS 15.