Visimation's ShapeSource stencils are designed for the broadest compatibility and ease of use and so we have elected to offer our products in a single file format that will work with all versions of Visio from 2002 and later. Visio introduced additional security features in Visio 2013 that require users to perform the following steps to enable pre-2013 stencils to work in Visio 2013. This will also work with Visio 2016 and later:
1. Select File > Options > Trust Center
2. Click button Trust Center Settings on the right side of the window
3. Click File Block Settings
4. Uncheck “Visio 2000-2002 Binary Drawings, Templates and Stencils"
5. Click OK at the bottom
6. Click OK at the bottom again
You should now be able to open the .vss files in the product you purchased.