Could you clarify exactly what the expected behaviour is around the actual downloads when ODR are unchanged/similar. The OP describes a case where the ODR is completely unchanged and would like the package to be immediately available. As you say "the system does not have any notion of understanding whether the files in an asset pack are identical across app versions". So the user/app must request the asset. Is the download process for the asset in any way optimised? If the asset has small changes, then perhaps it is delivered as a delta, so our users only download a small amount. If the asset is completely unchanged then perhaps the download only involves some meta data (a blank delta) so our users only download a tiny amount. From our testing it looks like there is no optimisation, but I don't know if that behaviour would be different for end users using the real app store as opposed to what we're seeing with testflight/promo codes. If it is as it seems, then I think it's quite a significant omission to not optimise the downloads of ODR to use deltas. It means our users will be unnecessarily downloading 100s of MB of data on each minor update. It must be costing Apple millions of dollars across the App Store to send this unnecessary data. It seems to be one of those rare situations where our Android users are getting a far smoother experience than our iOS users.

This issue appears to be fixed with XCode 13. Metal libraries compiled in XCode are now working on iOS 10 for us, so you may want to remove your workaround.