(on behalf of @kirvanp )
As far as the back buttons being gone on the iPhone version, I have noticed this since iOS 13 came out. I suggest updating the target to iOS 13.4, as the iPads are capable of running that, and doing the recommended adjustments to the code. Upgrading the target will make Xcode more willing to give warnings for code that was meant for iOS 10-12 that might no longer work. It will also result in a smaller app size as iOS 13 has the Swift runtime built into the OS rather than included with the app.

from ets.

Setting target to iOS13

When changing target to iOS 13; 47 warning of deprecated things from iOS 12 and 13 are found. Nothing about traitCollectionDidChange (see below).
Changing the target to iOS 13 will be a new project with specific issues to resolve deprecated usage.

Findings about the issue.

Found that traitCollectionDidChange not called at the same moment when on iOS 10 vs when on iOS 13.
For example, when the addAircraftPopover is shown under iOS 13, traitCollectionDidChange is not called. But if you change the orientation of the device, it is called and the "Done" button appears.
The function addOrRemoveDonButtonGivenTraitCollection is called from 8 other places.

Proposed changes

Proposed changes, for contexts similar to the one in AddAircraftPopover, is to remove the need of addOrRemoveDoneButtonGivenTraitCollection by adding the button for the specific trait.

from ets.

from ets.