The VDX file format is an XML-based drawing file format used by older versions of Microsoft Visio (specifically Visio 2002, 2003, and 2007). It stores vector graphics, text, and other drawing elements in a structured XML format. VDX files are used to create diagrams, flowcharts, organizational charts, network diagrams, and other types of technical and business drawings. While VDX was a standard format for Visio drawings for a period, it has been superseded by newer formats like VSDX (Visio Drawing) which is based on the Open Packaging Conventions (OPC) and offers improved features and compatibility. Opening VDX files in newer versions of Visio typically involves converting them to the VSDX format. The XML structure of VDX allows for programmatic manipulation and extraction of drawing data, although this is less common than working directly with the Visio application. VDX files are generally larger than their binary counterparts (VSD) due to the verbose nature of XML.