Previously, auto layout was interpreting the bottom of a UILabel to be the same as its baseline.

ENGADGET: Apple seeds iOS 6 beta 4 to developers: here's the changelog

The bottom edge of a UILabel view is now different from its baseline.

ENGADGET: Apple seeds iOS 6 beta 4 to developers: here's the changelog

It is unsupported to set values for the shadowOffset or shadowColor properties of a UILabel object if its attributedText property contains a valid attributed string.

ENGADGET: Apple seeds iOS 6 beta 4 to developers: here's the changelog

The NSTextAlignmentNatural value is unsupported and will throw an exception when used with the textAlignment property of UILabel or supplied as the alignment parameter to the drawInRect:withFont:lineBreakMode:alignment: method of NSString.

ENGADGET: Apple seeds iOS 6 beta 4 to developers: here's the changelog