Updated diagram templates:

• Visio 2013 offers improvements to several templates, including Timeline, Basic Network, Detailed Network, and Basic Shapes.
• New shapes and styles were added to the organization chart template, and the Business Process Modeling template added support for BPMN 2.0.
• The Database and UML templates are more flexible than before, with drag-and-drop functionality added.

File format, style, and theme changes:

• A new file format (.vsdx) is the default on the desktop and for viewing in a browser on SharePoint. Visio 2013 also reads and writes in .vssx, .vstx, .vsdm, .vssm, and .vstm formats.
• Visio 2013 provides some of the same formatting options used in other Office applications to your diagrams—including gradients, shadows, 3-D effects, and more.
• New themes add color and effects to diagrams, and variants for each theme make it easy to apply changes to an entire page.