Compared with iOS14, in iOS15 boundingRectWithSize:options: attributes: context: returns a different value. We found this maybe related to the attribute NSBaselineOffsetAttributeName and the option NSStringDrawingUsesFontLeading. For example, we use the same code:    UIFont *baseFont = [UIFont fontWithName:@"PingFangSC-Regular" size:16];   CGFloat baselineOffset = (29 - baseFont.lineHeight) / 4;   NSDictionary *baseTextAttributes = @{     NSFontAttributeName : baseFont,     NSParagraphStyleAttributeName : ({       NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];       [style setAlignment:NSTextAlignmentLeft];       [style setMinimumLineHeight:29];       [style setMaximumLineHeight:29];       style;     }),     NSKernAttributeName : @(0.25),     NSBaselineOffsetAttributeName : @(baselineOffset),   };   NSString *str = @"Compared with iOS14 in iOS15 boundingRectWithSize: options: attributes: context: returns a different value.";   NSAttributedString *attributeStr = [[NSAttributedString alloc] initWithString: str attributes:baseTextAttributes];   CGSize size = [attributeStr boundingRectWithSize:CGSizeMake(428, MAXFLOAT)                        options:(NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading | NSStringDrawingTruncatesLastVisibleLine)                        context:nil]     .size; In iPhone12 Pro Max iOS14, the return value is (CGSize) size = (width = 421.933999999997, height = 58) but in iOS15 the return value is (CGSize) size = (width = 421.93399999999997, height = 54.700000000000003) The difference between their heights happens to be equal to the baselineOffset times the number of lines. If I remove NSBaselineOffsetAttributeName during the initialization of attributeString , or remove the option NSStringDrawingUsesFontLeading during calculation time, the calculated heights are the same in iOS 14 and 15. Should I expect this difference between iOS14 and iOS15 or is this a bug? Thanks!