Your response was very insightful although i think my confusion stems from the weird mentions of the SDK in the iOS release notes. https://developer.apple.com/documentation/ios-ipados-release-notes it says ”learn about changes to the sdk” but if its all changes to the sdk then why is it the ios and not ios sdk release notes? whats apples definition of SDK? if changes are made from user updating the ios without needing developer to take action, calling it an sdk change is weird. IMO.

Asides, if an iOS version contains bug fixes, does the app need to be updated to that ios version for the fixes to happen or would the device os update suffice?

IMO the most important party here is the sdk developers. they need to know to not affect the client app.

I am not concerned for Apple's sake, I am concerned for the developer's application's sake, and the sdk developer's sake. Developers shouldn't just assume that the OS has every thing taken care of for them. And the Sdk developer might not know either so they do risky things. Then the app has mysterious bugs. @Etresoft

I get that sdk code is our responsibility, but the fact is, people dont know that the app shares the same sandbox as the sdk and so they might not know to consider that before adopting an sdk. or consider that when they make new files in the filesystem. This seems like an issue to me.

So far in my digging i found this documentation for identifying binary dp, but for Swift packages: https://developer.apple.com/documentation/xcode/identifying-binary-dependencies i am guessing the idea there is the same as in sdks added using cocoapods?

image here

I found answer to my own question: https://developer.apple.com/support/required-device-capabilities