Yes...did you look at the package?

[1] if the currency values as saved in the data file are more than 30
days old, or if the data file does not exist, the program tries
to download new data

[2] at any time, you can select the "update" choice from the menu
within gcur to update the values

[3] you can run gcur from the command-line with the "-u" option
(which could be put into the gcur.desktop file) in order to update
the values whenever the program is run