How do I force my calendar application to refresh a calendar subscription?

When you update a calendar subscription, this change is not reflected immediately in your calendar. The best option is to simply wait for 12 to 24 hours. The other option is to change the subscription identifier (usually not recommended). When the identifier is changed, Google doesn't find the calendar in its cache and is forced to download it.

To do this, please take a look at the refresh instructions for Google Calendar.