Microsoft Core XML Services consists of a set of components that implement the possibility to process XSLT (Extensible Stylesheet Language Transformation) instructions in an XML format.
The elements that make all this possible are an API, an XML parser and an XPath processor, which can be used wisely to output the desired result.
These components are interconnected and cannot function without each other; the XML data is organized into a tree structure by the parser, while the processor serves to convert the XML data to HTML format for display purposes.
In fewer and more simpler words, Microsoft Core XML Services is generally used to create and validate XML documents, but can also parse them. Another one of its jobs is to perform HTTP requests and to manage the replies.
However, different technologies have been added to it during its development and several were dropped, which means that its range of use depends on the version you are running. For instance, while MSXML 4.0, MSXML 5.0 and MSXML 6.0 feature support for XSD schemas, MSXML 3.0 and 6.0 do not.
The latest version is the only edition ever released with support for native 64-bit environments and is shipped with a wide array of Microsoft products, such as Windows XP SP3, Vista and 7, as well as
.NET Framework 3.0
Although this is the newest version, Microsoft draws attention that it should not be considered a replacement for versions such as 3.0 and 4.0, seeing as these still provide legacy features that have been excluded from the latest release.
The good news is that the three versions can coexist happily and can be used separately, without causing compatibility issues. Although this behavior is less common for software applications, in general, it pays off in MSXML’s case, which does not leave room for speculation.