Google recently announced that CalDAV access will only be available to whitelisted developers after September 16, 2013.
We are pleased to announce that BusyCal 2.0.5 has been released with support for Google's new CalDAV requirements, and Google has added BusyCal 2.0.5 to its whitelist.
The main change in BusyCal 2.0.5 is the use of OAuth 2.0 for authorization. When you first launch BusyCal 2.0.5, you will be presented with a login window requiring you to sign in to your Google account.
Next, if you're using Google's 2-Step Verification, you'll be prompted to enter the code sent to your mobile device.
Lastly, you must grant BusyCal access to manage your calendars.
Once you've granted BusyCal access, it will begin syncing with Google Calendar and you shouldn't notice any other differences in behavior.
Updating to BusyCal 2.0.5
BusyCal 2.0.5 is a free update for all BusyCal 2.0 customers.
Mac App Store customers can download the update from the Mac App Store
Trial users can replace their existing app with the new 30-day trial
BusyCal 1.6 and BusySync 2.3 are not affected
This change only affects BusyCal 2.0. BusyCal 1.6.x and earlier and BusySync 2.3.x and earlier do not use CalDAV for syncing with Google, and will continue syncing with Google without requiring any changes.