Even with the ideology that you cannot use beta SDKs and OS versions to upload apps to App Store Connect or TestFlight, there still is the issue that validation of an app fails in Xcode if Icon Composer was used. Is the expectation that Icon Composer icons won't allow you to validate in Xcode 26? I would assume otherwise. Icon Composer's whole draw (besides Liquid Glass) is that it manages app icon sizing for you, in one file, is it not?