This post is from the Activity iPhone Duo UIKit Q&A.
It seems that UITabAccessory creates its own constraints. What are the dos and don’ts in terms of constraints within the accessory view for iPhone Duo ?
UITabAccessory constraints
Hello! Our recommendation is to ensure you are using auto layout for your UI, and allow the system to update the size of the accessory automatically.
We always recommend that your app supports all devices in all orientations, so test your tab bar accessory in all configurations and orientations.
Thank you for your question!