For reasons of compatibility with legacy character sets such as ISO-8859-1 (as well as occasional mistakes) Unicode sometimes provides multiple representations of the same character. For example, the e with accent acute ( ) can be represented as either the single character #xE9 or with the two characters #x65 (e) followed by #x301 (combining accent acute). XML 1.1 suggests that all generators of XML text should normalize such alternatives into a canonical form. In this case, you should use the single character rather than the double character.
However, both forms are still accepted. Neither is malformed . Furthermore, parsers are explicitly prohibited from doing the normalization for the client program. They may merely report a nonfatal error if the XML is found to be unnormalized. In fact, this is nothing that parsers couldn't have done with XML 1.0, except that it didn't occur to anyone to do it. Normalization is more of a strongly recommended best practice than an actual change in the language.