I need to create an Addin against version 3.0.3 as thats the version currently installed. The SDK on the visual studio market place is 3.1. I get an error when I try to create a new Pro app.
Scroll down to "Assets". Download the vsix's (see image). Double-click to install.
Note: because u have previously installed a later version (3.1), u will need to uninstall those vsix's first. U cannot install an older version on top of a newer version.