PPTX is the latest file format for presentations created by using Microsoft PowerPoint. It has been introduced with version 2007 of the popular presentation tool. PPTX is based on an open XML data format and files that use it are ZIP-compressed for smaller size. Microsoft promised that it would publish the format specification for anyone to use and released free converters to make PPTX compatible with prior versions of its Office suite. PPTX documents are not fully compliant with the OpenDocument standard which provides the basis for another XML-based file format considered a true open format.