I have an old app, that is running even on old iOS11 at the moment. This poses a problem for me: I do not want to cut off all the people that rely on the app. but, 2. I want to upgrade to SwiftUI and use all the new possibilities that iOS14 brings. What should I do in this situation? If I release an update supporting only users having iOS14+ what happens to older users and people who are using older systems? Will they still be able to use the older version, or download it from the app store? Or I am technically cutting them off.

Hello, I have an old hybrid app used by people who have iOS versions between 11.0 and 14+.  I want to migrate the app to the native code and, to comply with the latest Apple's requirements, I would like to abandon IDFA and switch to SKAdNetwork. But I am not sure what I should do. Should I migrate to the UIKit and update all the old devices to comply with new IDFA requirements,  or  should I migrate the app to SwiftUI and update the devices compatible with iOS14+? Would I still be in line with the privacy requirements if only iOS14+ users will receive the update that changes IDFA to SKAdNetwork? I appreciate any answer, thank you.