This situation is quite common, such as when a namespace-aware application is built on top of a namespace-unaware parser. Another common situation is when you create an XML document with a namespace-unaware XML editor but process it with a namespace-aware application. Using the same document with both namespace-aware and namespace-unaware applications is possible because XML namespaces use XML syntax. That is, an XML document that uses XML namespaces is still an XML document and is recognized as such by namespace-unaware software. The only thing you need to be careful about when using the same document with both namespace-aware and namespace-unaware applications is when the namespace-unaware application requires the document to be valid. In this case, you must be careful to construct your document in a way that is both valid and conforms to the XML namespaces recommendation.