I have coded an Excel add-in using Visual C#. This add-in appears as a COM add-in in Excel. However, I am quite sure that it used to appear as an Excel/VSTO Add-In in Excel before an update of Visual Studio. (I know that I was able to access the Globals class. This thread says that Globals can only be accessed in Excel add-ins.)
So my question is: How can I make my COM add-in an Excel/VSTO add-in?