Apps built with two versions of Xcode perform differently on some APIs

I built two apps with Xcode 11 and Xcode 12, and run them on iPhone 12. Then I found that [UIScreen mainScreen] returns differently, 1125*2436 with Xcode 11 and 1170*2532 with Xcode 12. What causes this difference ? Are there other APIs having same problems?
Apps built with two versions of Xcode perform differently on some APIs
 
 
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