Ok, found the answer: the header view class can also be a UICollectionViewListCell, which provides the exact same mechanism as UITableViewHeaderFooterView.

Interesting, I did not know this header. It seems to do exactly what you would want: give the server a chance to reject the request before the upload of the body is even started. I added the header to the URLRequest, but that did not fix the problem. But that might very well be a problem on the server side. I'm still investigating that. So I guess that would be our best shot? Trying to make our server support this header?

It is not. At least not to my knowledge, and I don't see the "Transfer-Encoding: chunked" header on the server side (I don't know if I would though, or if the framework we are using on the server (Spring Boot) handles that transparently). Would that be a possible solution? If so, how would I enable chunked transfer encoding? I tried to just add the Transfer-Encoding header to the URLRequest, but that didn't seem to do anything.

Yes!

Correct! This is a normal call to URLSession.upload(for:from:delegate) while the app is in the foreground, not a background session. The URLSession is created by us, but with the URLSessionConfiguration.default and only with a custom user agent string. Everything else is left as is. I might also add that the server is also our own software. The way it works is the server receives the data until the allowed maximum is reached, then it sends the response and closes the connection, while the network layer is still trying to send the remaining data. But again, I could see in the diagnostics log that the response is received and read.

As suggested by https://twitter.com/hunter/status/1513960632059510784 I just deleted my local provisioning profile files which forced Xcode to generate them again and this fixed the issue for me.

So I just got a reply from Apple to a bug report I filed for this, and it turns out the propagation of safe area insets to a view with a scale or rotation transform is not supported. You have to apply the transform to a view deeper in the view hierarchy or handle it yourself some other way. Bummer, but good to know.

On what device did you test this? The bug is only relevant on iPhones with notch, i.e. without a home button. I should have clarified that, sorry. The following numbers are from an iPhone 12 emulator, with iOS 14.3. So the behavior is interesting. When the app starts with the UITableViewController as initial view controller, I also get 0 all around for the safe area insets: At load: at load UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0) after transform UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0) layout changed UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0) after rotation: no output, viewLayoutMarginsDidChange is not called. However, if I push to another view controller and then return, upon return: layout changed UIEdgeInsets(top: 143.0, left: 0.0, bottom: 34.0, right: 0.0) after rotation: again, no output I just double checked this on a real device (iPhone XS) and get the same results.

override func viewDidLoad() { 		super.viewDidLoad() 		tableView.transform = CGAffineTransform(scaleX: 1, y: -1) } That's all it takes. Instead of CGAffineTransform(scaleX: 1, y: -1) you can also just do CGAffineTransform(scaleX: 0.99, y: 0.99), it has the same effect on the safeAreaInsets not updating.

The transform is set in viewDidLoad. But I can reproduce the problem by setting the transform afterwards as well. The problem with just setting the insets myself is that I don't know where to get the correct values from, as the safeAreaInsets are not updated, which is the problem. Where else might I get the correct safe are insets values from?

I'm not sure I understand your question, but if you want to send a silent push notification to your app so it can update in the background, that is documented here: https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server/pushing_background_updates_to_your_app