We have found 3 software records in our database eligible for .vdx to .svg file format conversion.
Microsoft Visio can by default exports its diagrams and drawings to several formats, including the SVG and other common graphics format, or even some CAD formats like DWG.
If you do not have access to Visio, the easiest way would be to get your hands on some of the available converters like the VDXtoSVG tool, which you can download for free.
A diagram application, that uses vector graphics to create diagrams. Microsoft Visio is distributed as part of Microsoft Office Family and also available as a subscription through Microsoft Office 365. The latest version is Visio 2016 that is compatible with Windows 7, Windows 8 and Windows 10.
VDXtoSVG is a SourceForge project to create an XSLT spreadsheet that can translate VDX files to SVG.