When you update XCode it updates the sdk version, but do changes in the sdk take effect for apps running in a lower iOS version or only the corresponding iOS version or higher? For instance, https://developer.apple.com/documentation/ios-ipados-release-notes/ios-ipados-18_1-release-notes Do changes listed in the notes only happen for apps that are running on iOS 18.1 devices or on any device with the app compiled against the 18.1 sdk version? Am I the only person who finds the docs totally unclear on this?

Not sure if my question is weird or not, but I didnt find any documentation about an sdks access to an apps documents directory. Im assuming that because sdk is part of the sandbox that it can access and read from the documents directory? i.e. if i used NSFileManager.defaultManager.URLForDirectory( directory = NSCachesDirectory, inDomain = NSUserDomainMask, appropriateForURL = null, create = false, error = null, ) to write a file called "file.txt", then any sdk my app used has the ability to access the contents of said directory? If yes, why isnt this considered something more worth mentioning? usually in filemanager tutorials they never warn about this. FYI: Im asking more for iOS and iPadOs then MacOs.

Is it possible automatically grey out files that are too big when user select files using the UIDocumentPickerViewController?

https://developer.apple.com/documentation/ios-ipados-release-notes/ios-ipados-17_4-release-notes At the end of each release note there is a number, eg 121566625). What are these numbers?

Lets say i have an sdk that is not one of those listed, but it uses one of those listed. In this case, do i have to get the sdk im using to update their dependency to add the required signature and privacy manifest?

In https://developer.apple.com/support/third-party-SDK-requirements/ it says "Signatures are also required in these cases where the listed SDKs are used as binary dependencies. " As I am clueless regarding the technicalities of how sdks are added to a host app, the term binary dependency means nothing to me. For reference, our app uses Cocoapods to install all of the sdks.

I am assuming that even if the app i am using is not listed in the ios list of privacy impacting sdks, if they use a privacy impacting sdk in their sdk, then my app will be required to get the privacy manifest for that privacy impacting sdk: the rule must (logically!) be transitive. So far apple has not sent any email about the app needing to provide that for any of our sdks. but i am worried that maybe apple has not done the check for us yet, and by the time they do , we will be near deadline to submit an app.

For the PreviewProvider, is it possible to set the ios version which the preview will be made for or the preview will always use the latest ios version (e.g. ios 17)?

see the difference between the ios 15 screen shot and ios 17. the bottom one is the ios 17. if you look really closely you can see the whitespace is smaller. How can a developer make that new whitespace in code to follow the new style?

I am looking for a comparison chart between these three devices regarding what hardware each device support, showing every model of the devices.

I saw in https://developer.apple.com/videos/play/wwdc2023/10180/ at 12:51 that the CLBackgroundActivitySession will relaunch the app to resume location updates even if user closed the app (which I interpret to mean swiping the app from app switcher) -- despite the fact that the CLBackgroundActivitySession only require a when-in-use location permission. Since this api can give the app location updates even after the user swiped the app from the switcher, how is the api different than using the current always allow authorisation system to continuously record user movements? For the use case of continously tracking them whenever they move (let's say you wanted to record their driving behaviours), can't the app just launch the CLBackgroundActivitySession and continue to recreate this session every time the app is relaunched to keep on tracking?

"SafariViewController must be used to visibly present information to users; the controller may not be hidden or obscured by other views or layers. " I am not clear on what this is addressing. If an app has a link to the company's FAQ page on its website, is this page required to show up in the SFViewController? What if it showed up on the Safari web browser instead?

Tested on a iOS 16.2, when user on their first time on the app gets asked "allow once" or "allow while using" and they select "allow once", then after they close the app, reopen and gets asked "allow while using" or "always allow", they select "allow while using", CLLocationManager returns "always allow" permission status?

If you are a company with multiple brands that offer the same app product, can they all have similar UI? so the colours and font styles may differ but the layout and content are the same. for example, if you are a restaurant company and you own multiple different brands of pizza restaurants, and they all offer the same app for pizza delivery, can they all just have same UI? The section on copycats is not clear on this https://developer.apple.com/app-store/review/guidelines/#copycats

Is there a way for xcode to check if all localised strings have corresponding key in localised strings file?