You can generate attributed strings that work in UIKit, primarily UITextView and UILabel. You have to pass the DTUseiOS6Attributes option to the initWithHTMLData: method to enable iOS 6 compatible attributes. Note that these will only be used if actually running on a device with iOS 6 or higher.
In the demo app the first tap displays the attributed string with the traditional CoreText and custom attributes in a DTCoreTextAttributedTextView. The new "iOS 6" tab on the right (only visible on iOS 6 or higher) displays the attributed string with iOS 6 compatible attributes in a UITextView."
Normal Text, Strike Out, Underlined, Bold, Italic, SmallCapps
Setting a background color or changing the text color.
The text-shadow property is supported. Only a single shadow is supported. If multiple shadows are set via CSS then only the first is used.
Text with Shadow
Embossed
Glowing
Multiple Shadows
Lists work partially, because we have no access to the private tab stops property of NSParagraphStyle. This is causing some trouble on aligning "hanging" lines.
Support for changing the line height is broken in iOS 6. As soon as you have more than one font in the attributed string the minimum and maximum line height attributes of the paragraph style are being ignored.
Hyperlinks are not supported. UITextView does not have the NSLink attribute Mac has and there is no delegate protocol to deal with clicking on links.
Since there is no way to reserve extra space on a glyph there is no way to display custom views or inline images
Horizontal Rule (hr) is not supported.
Native lists and text boxes are private to NSParagraphStyle
The tab stops list is also private in NSParagraphStyle, lists only work by using the first standard tab stop as list indent.