Project Upgrade, Options dialog box
Applies to: 
Visual Studio 
Visual Studio for Mac
Note
This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
Use the Project Upgrade page to specify whether Visual Studio automatically changes VSTO Add-in projects to target the version of Office that is installed on the development computer.
To access this page, on the Tools menu, click Options. Expand the Office Tools folder, and then click Project Upgrade.
UIElement list
Always upgrade to installed version of Office This option is disabled for Visual Studio 2013 because Office projects in Visual Studio 2013 can target only Office 2010 or Microsoft Office 2013 applications. For more information, see Upgrade and migrate Office solutions.