A few days ago Gulden released the 1.6.4.8 update. As usual you can just close your Gulden app, download and replace it by this new release.

The list of improvements: 

UI – Introduce a new informational widget and other minor UI improvements that make it move obvious to users that the wallet is not yet available during initial sync.
UI – Add a new menu item for setting the currency.
UI – Fix a crash in the send dialog on machines with no network connection.
UI – Remove bitcoin payment option from send screen
CORE – Update checkpoints, static difficulties, static seeds and other static information to help assist new users with better syncing experience.