You can't upgrade to Quicken 16 because it has been replaced by a newer version that can be acquired from the official web page. Quicken 2015 supports US Dollars, Euros and Pound sterling currencies and can use older files if they are saved using the QDF format. By default, the multiple currencies feature is disabled, but you can activate it very easy. Select Preferences from the Edit menu, click Calendar and currency from the left pane, press Multicurrency support from the right one and then OK. If you have issues, use the official contact page to get in touch with the support team.
