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However, both forms are still accepted. Neither is malformed. Further-more, 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.
There's one other new feature that's effectively part of XML 1.1: name-spaces 1.1, which adds the ability to undeclare namespace prefix map-pings. For example, consider the following API element.
A system that was looking for qualified names in element content might accidentally confuse the public:void and private:int in the cpp element with qualified names instead of just part of C++ syntax (albeit ugly C++ syntax that no good programmer would write). Undeclaring the public and private prefixes allows them to stand out for what they actually are, just plain unadorned text.
In practice, however, very little code looks for qualified names in element content. Some code does look for these things in attribute values, but in those cases it's normally clear whether or not a given attribute can contain qualified names. Indeed this example is so forced precisely because prefix undeclaration is very rarely needed in practice and never needed if you're only using prefixes on element and attribute names.
That's it. There is nothing else new in XML 1.1. It doesn't move name-spaces or schemas into the core. It doesn't correct admitted mistakes in the design of XML such as attribute value normalization. It doesn't sim-plify XML by removing rarely used features like unparsed entities and notations. It doesn't even clear up the confusion about what parsers should and should not report. All it does is change the list of name and white space characters. This very limited benefit comes at an extremely high cost. There is a huge installed base of XML 1.0-aware parsers, browsers, databases, viewers, editors, and other tools that don't work with XML 1.1. They will report well-formedness errors when presented with an XML 1.1 document.
The disadvantages of XML 1.1 (including the cost in both time and money of upgrading all your software to support it) are just too great for the extremely limited benefits it provides most developers. If you're more comfortable working in Mongolian, Yi, Cambodian, Amharic, Dhivehi, or Burmese and you only need to exchange data with other speakers of one of these languages (for instance, you're developing a system exclusively for a local Amharic-language newspaper in Addis Ababa where everybody speaks Amharic), you can set the version attribute of the XML declara-tion to 1.1. Everyone else should stick to XML 1.0.
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Created: March 27, 2003
Revised: October 25, 2003
URL: http://webreference.com/programming/xml/1
