Baleegal!
XML 1.0 allows you to insert characters from the C1 control code range, whilst those from the C0 range are outright forbidden.
XML 1.1 allows you to insert characters from the C0 range as long as they are escaped as character entity references, and mandates that you do the same for those from the C1 range.
This little fact is the reason why not all XML 1.0-valid documents are valid under XML 1.1. Nasty.
