1.3. General PHP Changes
1.3.1. XML and Web Services
Following the changes in the language, the XML updates in PHP 5 are probably the most significant and exciting. The enhanced XML functionality in PHP 5 puts it on par with other web technologies in some areas and overtakes them in others.
126.96.36.199. The Foundation
XML support in PHP 4 was implemented using a variety of underlying XML libraries. SAX support was implemented using the old Expat library, XSLT was implemented using the Sablotron library (or using libxml2 via the DOM extension), and DOM was implemented using the more powerful libxml2 library by the GNOME project.
Using a variety of libraries did not make PHP 4 excel when it came to XML support. Maintenance was poor, new XML standards ...